Functions/GenXdev.Helpers.Physics/Get-FreeFallTime.cs
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// ################################################################################
// Part of PowerShell module : GenXdev.Helpers.Physics // Original cmdlet filename : Get-FreeFallTime.cs // Original author : René Vaessen / GenXdev // Version : 1.302.2025 // ################################################################################ // Copyright (c) René Vaessen / GenXdev // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // ################################################################################ using System; using System.Management.Automation; namespace GenXdev.Helpers.Physics { /// <summary> /// <para type="synopsis"> /// Calculates the time required for an object to fall a given height during free fall. /// </para> /// /// <para type="description"> /// This function calculates the time duration required for an object to fall a /// specified height using a numerical method that accounts for air resistance and /// terminal velocity. The calculation uses small time steps to accurately model /// the physics of falling objects with realistic terminal velocity constraints. /// </para> /// /// <para type="description"> /// PARAMETERS /// </para> /// /// <para type="description"> /// -HeightInMeters <double><br/> /// The height to fall in meters for which to calculate the time duration.<br/> /// - <b>Position</b>: 0<br/> /// - <b>Mandatory</b>: true<br/> /// </para> /// /// <para type="description"> /// -TerminalVelocityInMs <double><br/> /// The terminal velocity in meters per second. Defaults to 53 m/s which is the /// typical terminal velocity for a human in free fall.<br/> /// - <b>Position</b>: 1<br/> /// - <b>Default</b>: 53<br/> /// </para> /// /// <para type="description"> /// -As <string><br/> /// The unit for the output time. Defaults to 'seconds'.<br/> /// - <b>Position</b>: 2<br/> /// - <b>Default</b>: "seconds"<br/> /// - <b>Allowed values</b>: seconds, minutes, hours, milliseconds, days<br/> /// </para> /// /// <example> /// <para>Calculates the time required to fall 100 meters with default human terminal velocity.</para> /// <para>Detailed explanation of the example.</para> /// <code> /// Get-FreeFallTime -HeightInMeters 100 -TerminalVelocityInMs 53 /// </code> /// </example> /// /// <example> /// <para>Calculates the time required to fall 50 meters using positional parameter and default terminal velocity.</para> /// <para>Detailed explanation of the example.</para> /// <code> /// Get-FreeFallTime 50 /// </code> /// </example> /// /// <example> /// <para>Calculates the time required to fall 100 meters and returns the result in minutes.</para> /// <para>Detailed explanation of the example.</para> /// <code> /// Get-FreeFallTime -HeightInMeters 100 -As "minutes" /// </code> /// </example> /// </summary> [Cmdlet(VerbsCommon.Get, "FreeFallTime")] [OutputType(typeof(double))] public class GetFreeFallTimeCommand : PSGenXdevCmdlet { /// <summary> /// The height to fall in meters for which to calculate the time duration. /// </summary> [Parameter( Mandatory = true, Position = 0, HelpMessage = "The height to fall in meters" )] public double HeightInMeters { get; set; } /// <summary> /// The terminal velocity in meters per second (default: 53 m/s for human). /// </summary> [Parameter( Mandatory = false, Position = 1, HelpMessage = ("The terminal velocity in meters per second " + "(default: 53 m/s for human)") )] public double TerminalVelocityInMs { get; set; } = 53; /// <summary> /// The unit for the output time. /// </summary> [Parameter( Mandatory = false, Position = 2, HelpMessage = "The unit for the output time" )] [ValidateSet("seconds", "minutes", "hours", "milliseconds", "days")] public string As { get; set; } = "seconds"; /// <summary> /// Begin processing - initialization logic /// </summary> protected override void BeginProcessing() { WriteVerbose( "Starting free fall time calculation for " + HeightInMeters + " meters " + "with terminal velocity " + TerminalVelocityInMs + " m/s" ); } /// <summary> /// Process record - main cmdlet logic /// </summary> protected override void ProcessRecord() { // Define the acceleration due to gravity in meters per second squared double gravity = 9.81; // Set up numerical integration parameters for accurate calculation double dt = 0.01; // Initialize time tracking variable double time = 0; // Initialize height accumulator double height = 0; // Initialize velocity tracker double velocity = 0; // Perform numerical integration using small time steps until height is reached while (height < HeightInMeters) { // Apply air resistance model by capping velocity at terminal velocity if (velocity >= TerminalVelocityInMs) { // Maintain constant terminal velocity when reached velocity = TerminalVelocityInMs; } else { // Accelerate under gravity when below terminal velocity velocity += gravity * dt; } // Calculate distance traveled in this time step height += velocity * dt; // Advance time by one step time += dt; // Prevent infinite loops with safety timeout if (time > 1000) { WriteError(new ErrorRecord( new Exception("Calculation timeout exceeded 1000 seconds"), "CalculationTimeout", ErrorCategory.OperationTimeout, null )); WriteObject((double)0); return; } } WriteVerbose("Calculated fall time: " + time + " seconds"); // Convert to desired unit using PowerShell function var scriptBlock = ScriptBlock.Create( "param($Value, $FromUnit, $ToUnit) " + "GenXdev.Helpers\\Convert-PhysicsUnit -Value $Value -FromUnit $FromUnit -ToUnit $ToUnit" ); var results = scriptBlock.Invoke(time, "seconds", As); // Extract the result from PSObject double result = 0; if (results.Count > 0 && results[0].BaseObject is double) { result = (double)results[0].BaseObject; } // Return the calculated time as double WriteObject(result); } /// <summary> /// End processing - cleanup logic /// </summary> protected override void EndProcessing() { // No cleanup needed } } } |