A tool to help you understand and manipulate different weight variables in various contexts.
Weight Metric Calculator
The starting point for your weight measurement (e.g., kg, lbs).
Density Adjustment
Buoyancy Adjustment
Compression Factor
Expansion Factor
Select the type of variable to adjust.
A multiplier or divisor for the adjustment (e.g., 1.5 for increasing density, 0.8 for decreasing).
Required for density/buoyancy calculations (e.g., m³, ft³).
Calculation Results
—
Adjusted Weight: —
Effective Density: —
Net Force: —
Formula Used: The calculations adapt based on the selected variable type. For density adjustments, it might be (Base Weight * Adjustment Factor) / Volume. For buoyancy, it involves fluid density and displaced volume.
Calculation Breakdown Table
Metric
Value
Unit
Base Weight
—
N/A
Variable Type
—
N/A
Adjustment Factor
—
N/A
Volume/Area
—
N/A
Adjusted Weight
—
N/A
Effective Density
—
N/A
Net Force
—
N/A
Weight Variable Impact Chart
Key Assumptions
Units are assumed to be consistent (e.g., kg for weight, m³ for volume). Gravity (g) is assumed as 9.81 m/s² for net force calculations.
What is Calculating Weight Variables?
Calculating weight variables refers to the process of determining how changes in physical properties or external forces affect the perceived or actual weight of an object. This is a fundamental concept in physics and engineering, crucial for understanding everything from structural integrity to fluid dynamics. It's not about changing the mass of an object, but rather how its weight, which is the force of gravity acting upon its mass, is influenced by other factors like density, buoyancy, or applied forces. This calculation is vital for engineers designing structures, naval architects, material scientists, and even athletes optimizing their performance.
A common misconception is that "weight variables" implies altering the object's mass. In reality, mass is invariant. Weight, however, is a force (mass * acceleration due to gravity), and this force can be modified by changes in the gravitational field (less common on Earth) or, more practically, by opposing forces like buoyancy. Another misconception is that all weight adjustments are proportional; often, complex formulas involving density, volume, and external forces lead to non-linear changes.
Understanding weight variables is essential for anyone working with physical objects in different environments or under varying conditions. Whether you are calculating the load on a bridge, the lift required for an aircraft, or the apparent weight of an object submerged in water, accurate weight variable calculations are key to safety and efficiency.
Weight Variable Formula and Mathematical Explanation
The core idea behind calculating weight variables is to understand how different physical phenomena alter the force we perceive as weight. Weight itself is fundamentally defined by Newton's second law, F = ma, where 'F' is the force (weight), 'm' is the mass, and 'a' is the acceleration due to gravity (often denoted as 'g'). So, the basic weight equation is:
W = m * g
However, "calculating weight variables" usually involves adjusting this base weight due to other factors. Let's break down some common scenarios:
1. Density Adjustment:
Density (ρ) is mass (m) per unit volume (V): ρ = m / V. If you know the base weight (W) and you want to find the new weight under a different density environment (assuming mass remains constant, but perhaps the object's composition changes, or it's a hypothetical scenario), you'd first find the mass and then recalculate weight:
Mass (m) = Base Weight (W) / g
New Density (ρ_new) = Original Density (ρ_orig) * Adjustment Factor
New Mass (m_new) = New Density (ρ_new) * Volume (V)
Adjusted Weight (W_adj) = New Mass (m_new) * g
Or, more directly if the adjustment factor relates to the density itself:
W_adj = (W / V) * V_new * g, where V_new is calculated based on the adjusted density.
A simpler approach often used is to directly adjust the *apparent* weight based on a factor that implicitly accounts for density changes: W_adj = W * Factor, where 'Factor' might represent the ratio of new density to old density.
2. Buoyancy Adjustment:
Archimedes' principle states that the buoyant force (F_b) on an object submerged in a fluid is equal to the weight of the fluid displaced by the object. The apparent weight (W_app) is the actual weight minus the buoyant force.
Buoyant Force (F_b) = Density of Fluid (ρ_fluid) * Volume of Submerged Object (V_sub) * g
Apparent Weight (W_app) = Actual Weight (W) – Buoyant Force (F_b)
W_app = (m * g) – (ρ_fluid * V_sub * g)
3. Compression/Expansion Factors:
These factors typically adjust the effective volume or density. If an 'Expansion Factor' of 1.2 is applied, it might mean the volume increases by 20%, thus decreasing the density and apparent weight for a constant mass. Conversely, a 'Compression Factor' might increase density.
Effective Volume (V_eff) = Original Volume (V) * Expansion Factor
Effective Density (ρ_eff) = Mass (m) / Effective Volume (V_eff)
Or, if the factor directly modifies the density:
Effective Density (ρ_eff) = Original Density (ρ_orig) * Compression/Expansion Factor
The resulting "weight variable" could be the new apparent weight based on this effective density.
Variables Table:
Variable
Meaning
Unit
Typical Range / Notes
Base Weight (W)
The gravitational force on an object's mass under standard conditions.
Newtons (N), Pounds (lbs)
Depends on mass and gravity.
Mass (m)
The amount of matter in an object.
Kilograms (kg), Slugs
Constant for an object.
Acceleration due to Gravity (g)
The rate at which an object accelerates towards the center of a gravitational body.
m/s², ft/s²
Approx. 9.81 m/s² on Earth.
Density (ρ)
Mass per unit volume.
kg/m³, g/cm³
Varies significantly by substance.
Volume (V)
The three-dimensional space occupied by an object.
m³, cm³, ft³
Depends on object's dimensions.
Adjustment Factor
A multiplier or divisor applied to change density, volume, or apparent weight.
Unitless
>1 increases, <1 decreases. Context-dependent.
Buoyant Force (F_b)
Upward force exerted by a fluid that opposes the weight of an immersed object.
Newtons (N), Pounds (lbs)
Depends on displaced fluid density and volume.
Apparent Weight (W_app)
The perceived weight of an object, accounting for forces like buoyancy.
Newtons (N), Pounds (lbs)
W – F_b. Can be less than actual weight.
Practical Examples (Real-World Use Cases)
Example 1: Calculating Apparent Weight in Water
A solid steel block has a mass of 100 kg. We want to find its apparent weight when fully submerged in fresh water. Assume the density of steel is 7850 kg/m³ and the density of water is 1000 kg/m³. The volume of the steel block is V = mass / density = 100 kg / 7850 kg/m³ ≈ 0.0127 m³.
Inputs:
Base Mass (m): 100 kg
Acceleration due to Gravity (g): 9.81 m/s²
Density of Fluid (ρ_fluid – water): 1000 kg/m³
Volume of Submerged Object (V_sub): 0.0127 m³
Calculations:
Actual Weight (W) = m * g = 100 kg * 9.81 m/s² = 981 N
Buoyant Force (F_b) = ρ_fluid * V_sub * g = 1000 kg/m³ * 0.0127 m³ * 9.81 m/s² ≈ 124.6 N
Apparent Weight (W_app) = W – F_b = 981 N – 124.6 N ≈ 856.4 N
Result Interpretation: The steel block appears to weigh approximately 856.4 Newtons when submerged, which is significantly less than its actual weight of 981 Newtons due to the upward buoyant force of the water. This is crucial for designing ships and submarines.
Example 2: Density Adjustment for Material Science
A new alloy is being developed. The base material has a density of 2700 kg/m³ (like Aluminum). Scientists want to increase its density by 20% using a specific alloying process. We need to understand the impact on weight for a standard sample size.
Inputs:
Original Density (ρ_orig): 2700 kg/m³
Adjustment Factor: 1.20 (to increase density by 20%)
Volume of Sample (V): 0.01 m³
Acceleration due to Gravity (g): 9.81 m/s²
Calculations:
Mass (m) = ρ_orig * V = 2700 kg/m³ * 0.01 m³ = 27 kg
Base Weight (W) = m * g = 27 kg * 9.81 m/s² ≈ 264.87 N
New Density (ρ_new) = ρ_orig * Adjustment Factor = 2700 kg/m³ * 1.20 = 3240 kg/m³
New Mass (m_new) = ρ_new * V = 3240 kg/m³ * 0.01 m³ = 32.4 kg
Adjusted Weight (W_adj) = m_new * g = 32.4 kg * 9.81 m/s² ≈ 317.96 N
Result Interpretation: Even though the volume of the sample remained the same, increasing the density by 20% increased its mass from 27 kg to 32.4 kg, resulting in a higher weight of approximately 317.96 N. This helps material scientists predict how structural components will perform under load.
How to Use This Weight Variable Calculator
Our Weight Variable Calculator is designed for simplicity and accuracy. Follow these steps to get your results:
Enter Base Weight: Input the initial weight of your object. Ensure you use consistent units (e.g., kilograms or pounds).
Select Variable Type: Choose the physical phenomenon you wish to simulate from the dropdown menu:
Density Adjustment: For scenarios where the material's density changes, affecting its weight for a given volume.
Buoyancy Adjustment: To calculate the apparent weight of an object submerged in a fluid.
Compression Factor: Simulates increased density or reduced volume.
Expansion Factor: Simulates decreased density or increased volume.
Input Adjustment Factor: Provide a numerical value that represents the magnitude of the change. For example, entering 1.5 for a density adjustment implies a 50% increase in density. Entering 0.8 implies a 20% decrease.
Enter Volume/Area (if applicable): This field is crucial for density and buoyancy calculations. If you are adjusting density, this is the volume of the object. If calculating buoyancy, this is the volume of the object submerged in the fluid.
Click Calculate: Once all fields are populated, press the "Calculate" button.
Reading Your Results:
Main Highlighted Result: This will typically show the final adjusted or apparent weight, providing the primary metric you're looking for.
Intermediate Values: These offer insights into the calculation process, showing values like the adjusted weight before buoyancy, the effective density, or the net force involved.
Calculation Breakdown Table: This table provides a detailed view of all input parameters and calculated outputs, including units, for verification and deeper understanding.
Chart: Visualizes the relationship between key variables, helping to grasp the impact of changes.
Decision-Making Guidance:
Use the results to make informed decisions. For instance, if the apparent weight in water is significantly lower than the actual weight, you might need stronger support structures or different handling methods. If adjusted weight due to density changes is higher, ensure your materials can withstand the increased load. The calculator helps quantify these effects.
Remember to use the Reset button to clear the form and start fresh, and the Copy Results button to easily transfer your findings elsewhere.
Key Factors That Affect Weight Variable Results
Several factors can significantly influence the outcome of weight variable calculations. Understanding these is crucial for accurate modeling and real-world application:
Mass of the Object: This is the most fundamental factor. Weight is directly proportional to mass (W = mg). Changes in composition that alter mass will change weight, assuming gravity remains constant.
Acceleration due to Gravity (g): While often assumed constant on Earth's surface, gravity varies slightly with altitude and geographic location. For extraterrestrial applications or high-precision scenarios, the specific value of 'g' is critical.
Density of the Object: For a constant mass, changes in an object's density (often due to compression or expansion) will alter its volume. This impacts buoyancy and how it interacts with its environment.
Volume of the Object: Especially relevant for buoyancy and density calculations. A larger volume displaces more fluid, increasing buoyant force. For density adjustments, the effective volume might change based on applied factors.
Density of the Surrounding Fluid (for Buoyancy): The greater the density of the fluid (e.g., saltwater vs. freshwater, air vs. helium), the greater the buoyant force exerted on a submerged object.
Shape and Orientation: While the total volume is key for buoyancy, the shape can influence stability and how fluid flows around the object, potentially affecting dynamic forces. For simple static calculations, volume is paramount.
External Applied Forces: Beyond gravity and buoyancy, other forces (like thrust, drag, or applied mechanical forces) can affect the net force acting on an object, influencing its perceived state of motion or equilibrium, though not its fundamental weight.
Temperature: Temperature affects the density of both solids and fluids. Materials may expand or contract with temperature changes, altering volume and thus density and apparent weight. This is particularly important in engineering applications operating across a wide temperature range.
Frequently Asked Questions (FAQ)
Q1: Does calculating weight variables change the object's mass?
No, mass is an intrinsic property of matter and remains constant. Weight is the force of gravity acting on that mass. Weight variables adjust the *apparent* or *effective* weight by introducing opposing forces (like buoyancy) or by considering changes in density/volume under specific conditions.
Q2: What's the difference between weight and mass?
Mass is the amount of 'stuff' in an object, measured in kilograms or slugs. Weight is the force exerted on that mass by gravity, measured in Newtons or pounds. Weight changes depending on the gravitational field, while mass does not.
Q3: Why is Volume/Area needed for some calculations?
Volume is essential for density (mass/volume) and buoyancy (weight of displaced fluid, which depends on volume) calculations. Area might be relevant in specific fluid dynamics or pressure-related contexts, but volume is generally the key geometric property for buoyancy and density.
Q4: Can the calculator handle negative weight variables?
The calculator is designed for standard physical scenarios. Negative inputs for base weight or adjustment factors might lead to physically nonsensical results. Ensure your inputs reflect realistic physical conditions.
Q5: How does temperature affect these calculations?
Temperature changes can alter the density of materials and fluids through expansion and contraction. While this calculator doesn't directly input temperature, it's an underlying factor affecting the density values you might use.
Q6: What does an "Adjustment Factor" of less than 1 mean?
An adjustment factor less than 1 typically signifies a decrease. For density, it means the material becomes less dense (e.g., expands). For buoyancy, it might relate to a fluid less dense than the object. For compression/expansion, it directly implies a reduction in the effective density or volume.
Q7: Is this calculator useful for calculating lift forces?
While related, lift forces (like those on airplane wings) are primarily generated by aerodynamics (Bernoulli's principle and Newton's third law), not just simple buoyancy. This calculator focuses on static weight adjustments due to density and buoyancy.
Q8: Can I use this calculator for objects in the air?
Yes, air has density and exerts a buoyant force. However, for most common objects on Earth, the density of air is significantly lower than the object's density, making the air's buoyant effect minimal compared to its weight. For very light objects (like balloons) or precise measurements, air buoyancy becomes more relevant.
function validateInput(id, errorId, message, minValue = null, maxValue = null) {
var input = document.getElementById(id);
var errorDiv = document.getElementById(errorId);
var value = parseFloat(input.value);
errorDiv.textContent = "; // Clear previous error
if (input.value.trim() === ") {
errorDiv.textContent = 'This field is required.';
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if (isNaN(value)) {
errorDiv.textContent = 'Please enter a valid number.';
return false;
}
if (minValue !== null && value maxValue) {
errorDiv.textContent = message || `Value must be less than or equal to ${maxValue}.`;
return false;
}
return true;
}
function calculateWeightVariables() {
var isValid = true;
// Validate all inputs
isValid &= validateInput('baseWeight', 'baseWeightError', 'Base weight cannot be negative.', 0);
isValid &= validateInput('adjustmentFactor', 'adjustmentFactorError', 'Adjustment factor cannot be negative.', 0);
// Volume/Area is only required for specific types, basic validation here
var variableType = document.getElementById('variableType').value;
if (variableType === 'density' || variableType === 'buoyancy') {
isValid &= validateInput('volumeOrArea', 'volumeOrAreaError', 'Volume/Area cannot be negative.', 0.000001); // Must be > 0 for density/buoyancy
} else {
document.getElementById('volumeOrAreaError').textContent = "; // Clear error if not required
}
if (!isValid) {
document.getElementById('resultsContainer').style.display = 'none';
return;
}
var baseWeight = parseFloat(document.getElementById('baseWeight').value);
var adjustmentFactor = parseFloat(document.getElementById('adjustmentFactor').value);
var variableType = document.getElementById('variableType').value;
var volumeOrArea = parseFloat(document.getElementById('volumeOrArea').value);
var resultsContainer = document.getElementById('resultsContainer');
var mainResultElement = document.getElementById('mainResult');
var intermediate1Element = document.getElementById('intermediate1');
var intermediate2Element = document.getElementById('intermediate2');
var intermediate3Element = document.getElementById('intermediate3');
var tableBaseWeight = document.getElementById('tableBaseWeight');
var tableVariableType = document.getElementById('tableVariableType');
var tableAdjustmentFactor = document.getElementById('tableAdjustmentFactor');
var tableVolumeArea = document.getElementById('tableVolumeArea');
var tableAdjustedWeight = document.getElementById('tableAdjustedWeight');
var tableEffectiveDensity = document.getElementById('tableEffectiveDensity');
var tableNetForce = document.getElementById('tableNetForce');
var g = 9.81; // Standard gravity in m/s^2
var adjustedWeight, effectiveDensity, netForce;
var baseWeightUnit = "N"; // Assume Newtons initially
var volumeAreaUnit = "m³"; // Assume cubic meters initially
var effectiveDensityUnit = "kg/m³";
var netForceUnit = "N";
// Infer units based on typical usage or leave generic
// For simplicity, assuming SI units (kg, m, N) primarily.
if (variableType === 'density') {
// Assuming baseWeight is already mass * g (e.g., Newtons)
// If baseWeight is mass (kg), then:
// var mass = baseWeight;
// var originalDensity = mass / volumeOrArea;
// effectiveDensity = originalDensity * adjustmentFactor;
// adjustedWeight = effectiveDensity * volumeOrArea * g;
// Simpler model: Assuming baseWeight is a measure that scales with density.
// Let's assume Base Weight is in N, and we want to see how changing density affects apparent weight.
// This requires knowing the original density and volume.
// A more direct approach for the calculator: adjust the *force* proportional to density change.
// Assume baseWeight is the actual weight (N).
// We need mass to calculate density: mass = baseWeight / g;
// originalDensity = mass / volumeOrArea;
// adjustedWeight = originalDensity * adjustmentFactor * volumeOrArea * g;
// Let's refine the model: If baseWeight is a force (N), and we adjust density,
// it implies a change in mass for the SAME volume.
// Mass_initial = baseWeight / g
// Density_initial = Mass_initial / volumeOrArea
// Density_new = Density_initial * adjustmentFactor
// Mass_new = Density_new * volumeOrArea
// adjustedWeight = Mass_new * g
var mass_initial = baseWeight / g; // kg
var density_initial = mass_initial / volumeOrArea; // kg/m³
effectiveDensity = density_initial * adjustmentFactor; // kg/m³
var mass_new = effectiveDensity * volumeOrArea; // kg
adjustedWeight = mass_new * g; // N
netForce = adjustedWeight; // In this context, adjusted weight is the net force.
effectiveDensityUnit = "kg/m³";
baseWeightUnit = "N";
volumeAreaUnit = "m³";
} else if (variableType === 'buoyancy') {
// Assume baseWeight is the actual weight in N
// volumeOrArea is the submerged volume in m³
// We need density of the fluid. Let's assume water (1000 kg/m³) by default,
// or we could add another input for fluid density.
// For this calculator, let's assume adjustmentFactor modifies the FLUID DENSITY.
var fluidDensity = 1000 * adjustmentFactor; // Assuming default fluid density is 1000 kg/m³
var buoyantForce = fluidDensity * volumeOrArea * g;
adjustedWeight = baseWeight – buoyantForce; // Apparent weight in N
// Calculate effective density of the submerged object IF its mass were equal to apparent weight / g.
// This is conceptually tricky. Let's focus on the buoyant force's effect.
effectiveDensity = baseWeight / (volumeOrArea * g); // Approx original object density if fully submerged
netForce = adjustedWeight; // Apparent weight is the net force supporting it.
effectiveDensityUnit = "kg/m³ (Object)";
baseWeightUnit = "N";
volumeAreaUnit = "m³";
} else if (variableType === 'compression') {
// Assume baseWeight is N. Compression increases density.
// Similar to density adjustment, but conceptually implies reducing volume for same mass or increasing density for same volume.
// Let's assume it increases density by a factor.
var mass_initial = baseWeight / g; // kg
var density_initial = mass_initial / volumeOrArea; // kg/m³
effectiveDensity = density_initial * adjustmentFactor; // Compression factor > 1 increases density
var mass_new = effectiveDensity * volumeOrArea; // kg
adjustedWeight = mass_new * g; // N
netForce = adjustedWeight;
effectiveDensityUnit = "kg/m³";
baseWeightUnit = "N";
volumeAreaUnit = "m³";
} else if (variableType === 'expansion') {
// Assume baseWeight is N. Expansion decreases density.
var mass_initial = baseWeight / g; // kg
var density_initial = mass_initial / volumeOrArea; // kg/m³
effectiveDensity = density_initial * adjustmentFactor; // Expansion factor < 1 decreases density
var mass_new = effectiveDensity * volumeOrArea; // kg
adjustedWeight = mass_new * g; // N
netForce = adjustedWeight;
effectiveDensityUnit = "kg/m³";
baseWeightUnit = "N";
volumeAreaUnit = "m³";
}
// Set results
mainResultElement.textContent = adjustedWeight.toFixed(2) + ' ' + baseWeightUnit;
intermediate1Element.innerHTML = 'Adjusted Weight: ' + adjustedWeight.toFixed(2) + ' ' + baseWeightUnit;
intermediate2Element.innerHTML = 'Effective Density: ' + (effectiveDensity !== undefined ? effectiveDensity.toFixed(2) : '–') + ' ' + effectiveDensityUnit;
intermediate3Element.innerHTML = 'Net Force: ' + netForce.toFixed(2) + ' ' + netForceUnit;
// Update table
tableBaseWeight.textContent = baseWeight.toFixed(2);
tableVariableType.textContent = variableType.charAt(0).toUpperCase() + variableType.slice(1);
tableAdjustmentFactor.textContent = adjustmentFactor.toFixed(2);
tableVolumeArea.textContent = (volumeOrArea !== undefined && !isNaN(volumeOrArea)) ? volumeOrArea.toFixed(3) : '–';
tableAdjustedWeight.textContent = adjustedWeight.toFixed(2);
tableEffectiveDensity.textContent = (effectiveDensity !== undefined && !isNaN(effectiveDensity)) ? effectiveDensity.toFixed(2) : '–';
tableNetForce.textContent = netForce.toFixed(2);
document.getElementById('baseWeightUnit').textContent = baseWeightUnit;
document.getElementById('volumeAreaUnit').textContent = volumeAreaUnit;
document.getElementById('adjustedWeightUnit').textContent = baseWeightUnit;
document.getElementById('effectiveDensityUnit').textContent = effectiveDensityUnit;
document.getElementById('netForceUnit').textContent = netForceUnit;
resultsContainer.style.display = 'block';
// Update chart
updateChart(variableType, baseWeight, adjustmentFactor, volumeOrArea, adjustedWeight, effectiveDensity);
}
function updateChart(variableType, baseWeight, adjustmentFactor, volumeOrArea, adjustedWeight, effectiveDensity) {
var ctx = document.getElementById('weightChart').getContext('2d');
if (window.weightChartInstance) {
window.weightChartChartInstance.destroy();
}
var labels = [];
var dataSeries1 = []; // e.g., Adjusted Weight
var dataSeries2 = []; // e.g., Effective Density
var chartTitle = 'Weight Variable Impact';
// Generate data points for the chart based on adjustment factor variations
var startFactor = 0.5;
var endFactor = 1.5;
var step = (endFactor – startFactor) / 10;
for (var i = 0; i <= 10; i++) {
var currentFactor = startFactor + i * step;
var tempAdjustedWeight, tempEffectiveDensity;
if (variableType === 'density' || variableType === 'compression' || variableType === 'expansion') {
var g = 9.81;
var mass_initial = baseWeight / g;
var density_initial = mass_initial / volumeOrArea;
tempEffectiveDensity = density_initial * currentFactor;
var mass_new = tempEffectiveDensity * volumeOrArea;
tempAdjustedWeight = mass_new * g;
labels.push(currentFactor.toFixed(2));
dataSeries1.push(tempAdjustedWeight);
dataSeries2.push(tempEffectiveDensity);
} else if (variableType === 'buoyancy') {
var g = 9.81;
var fluidDensity = 1000 * currentFactor; // Adjusting fluid density
var buoyantForce = fluidDensity * volumeOrArea * g;
tempAdjustedWeight = baseWeight – buoyantForce;
// For buoyancy, effective density isn't as straightforward to plot against the factor.
// Let's plot Adjusted Weight vs. Fluid Density Multiplier (currentFactor)
dataSeries1.push(tempAdjustedWeight);
dataSeries2.push(fluidDensity); // Show the fluid density used
labels.push(currentFactor.toFixed(2));
}
}
window.weightChartInstance = new Chart(ctx, {
type: 'line',
data: {
labels: labels,
datasets: [{
label: 'Adjusted Weight (N)',
data: dataSeries1,
borderColor: '#004a99',
fill: false,
yAxisID: 'y1'
}, {
label: (variableType === 'buoyancy' ? 'Fluid Density (kg/m³)' : 'Effective Density (kg/m³)'),
data: dataSeries2,
borderColor: '#28a745',
fill: false,
yAxisID: 'y2'
}]
},
options: {
responsive: true,
maintainAspectRatio: true,
plugins: {
title: {
display: true,
text: chartTitle
},
tooltip: {
mode: 'index',
intersect: false,
}
},
hover: {
mode: 'nearest',
intersect: true
},
scales: {
x: {
title: {
display: true,
text: 'Adjustment Factor / Fluid Density Multiplier'
}
},
y1: {
type: 'linear',
position: 'left',
title: {
display: true,
text: 'Weight (N)'
},
grid: {
drawOnChartArea: false, // only want the grid lines for one axis to show
}
},
y2: {
type: 'linear',
position: 'right',
title: {
display: true,
text: (variableType === 'buoyancy' ? 'Fluid Density (kg/m³)' : 'Density (kg/m³)')
},
// You can uncomment this if you want the scales to stack differently
// suggestedMin: 0,
}
}
}
});
}
function resetForm() {
document.getElementById('baseWeight').value = '100'; // Sensible default weight in kg for mass, N for force. Let's use N.
document.getElementById('variableType').value = 'density';
document.getElementById('adjustmentFactor').value = '1.0';
document.getElementById('volumeOrArea').value = '0.1'; // Sensible default volume in m^3
// Clear errors
document.getElementById('baseWeightError').textContent = '';
document.getElementById('variableTypeError').textContent = '';
document.getElementById('adjustmentFactorError').textContent = '';
document.getElementById('volumeOrAreaError').textContent = '';
// Reset results display
document.getElementById('mainResult').textContent = '–';
document.getElementById('intermediate1').innerHTML = 'Adjusted Weight: –';
document.getElementById('intermediate2').innerHTML = 'Effective Density: –';
document.getElementById('intermediate3').innerHTML = 'Net Force: –';
document.getElementById('resultsContainer').style.display = 'none';
// Clear table
document.getElementById('tableBaseWeight').textContent = '–';
document.getElementById('tableVariableType').textContent = '–';
document.getElementById('tableAdjustmentFactor').textContent = '–';
document.getElementById('tableVolumeArea').textContent = '–';
document.getElementById('tableAdjustedWeight').textContent = '–';
document.getElementById('tableEffectiveDensity').textContent = '–';
document.getElementById('tableNetForce').textContent = '–';
// Clear chart
if (window.weightChartInstance) {
window.weightChartInstance.destroy();
window.weightChartInstance = null;
}
var canvas = document.getElementById('weightChart');
var ctx = canvas.getContext('2d');
ctx.clearRect(0, 0, canvas.width, canvas.height);
}
function copyResults() {
var mainResult = document.getElementById('mainResult').textContent;
var intermediate1 = document.getElementById('intermediate1').textContent.replace('Adjusted Weight: ', ");
var intermediate2 = document.getElementById('intermediate2').textContent.replace('Effective Density: ', ");
var intermediate3 = document.getElementById('intermediate3').textContent.replace('Net Force: ', ");
var assumptions = document.querySelector('.key-assumptions p').textContent;
var textToCopy = "Calculation Results:\n";
textToCopy += "——————–\n";
textToCopy += "Main Result: " + mainResult + "\n";
textToCopy += "Adjusted Weight: " + intermediate1 + "\n";
textToCopy += "Effective Density: " + intermediate2 + "\n";
textToCopy += "Net Force: " + intermediate3 + "\n\n";
textToCopy += "Key Assumptions: " + assumptions + "\n";
// Attempt to copy using the Clipboard API
navigator.clipboard.writeText(textToCopy).then(function() {
alert('Results copied to clipboard!');
}).catch(function(err) {
console.error('Failed to copy text: ', err);
// Fallback for older browsers or if clipboard access is denied
var textArea = document.createElement("textarea");
textArea.value = textToCopy;
textArea.style.position = "fixed";
textArea.style.left = "-9999px";
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
try {
document.execCommand('copy');
alert('Results copied to clipboard!');
} catch (e) {
alert('Failed to copy. Please copy manually.');
console.error('Copy command failed: ', e);
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document.body.removeChild(textArea);
});
}
// Initial calculation on page load if default values are set
document.addEventListener('DOMContentLoaded', function() {
resetForm(); // Set default values and clear results
calculateWeightVariables(); // Perform initial calculation with defaults
});
// Add Chart.js library dynamically if not present
function loadChartJs() {
if (typeof Chart === 'undefined') {
var script = document.createElement('script');
script.src = 'https://cdn.jsdelivr.net/npm/chart.js@3.9.1/dist/chart.min.js'; // Use a specific, reliable version
script.onload = function() {
console.log('Chart.js loaded.');
// Recalculate if chart needs to be drawn initially
if (document.getElementById('resultsContainer').style.display === 'block') {
calculateWeightVariables();
}
};
script.onerror = function() {
console.error('Failed to load Chart.js.');
};
document.head.appendChild(script);
} else {
console.log('Chart.js already loaded.');
// Ensure chart is drawn if results are already visible
if (document.getElementById('resultsContainer').style.display === 'block') {
calculateWeightVariables();
}
}
}
// Call loadChartJs when the page is ready or when calculation is triggered
document.addEventListener('DOMContentLoaded', loadChartJs);
// Also ensure it's loaded before the first calculate call potentially needs it
var originalCalculate = window.calculateWeightVariables;
window.calculateWeightVariables = function() {
loadChartJs(); // Ensure Chart.js is loaded before attempting to draw
originalCalculate();
};