How to calculate velocity using Java

By Smitha S Maganti

In this demo, we are going to learn how to calculate the final velocity of an object or a body in Java. We will be taking time, acceleration, displacement, and initial velocity as the parameters.

Calculating the velocity in Java

Formulae to calculate velocity:

There are two general formulae to calculate velocity, v:

1. v = u + a*t
2. v^2 = u^2 + 2*a*s

where,
u is the initial velocity in m/s,
a is the acceleration in m/s^2,
s is the displacement in meters, and
t is the time taken in seconds.

Steps to write the program:

Step 1: Define variables u, a, s, and t of float data type to represent the parameters.
Step 2: Take the input of initial velocity and acceleration from the user.
Step 3: Ask the user if the third parameter used to calculate the velocity is time or displacement.
Step 4: Depending on the third parameter, use the appropriate formula to calculate the velocity, and store it in a variable v of float data type.
Step 5: Print the value of velocity stored in v.

Java program to calculate velocity of an object:

import java.util.Scanner;
import java.lang.Math;

public class velocity {
  
  public static void main(String[] args){
    float v, u, a, s, t;
    String c; //Variable to store the choice of third parameter.
    
    /*Getting the values of u and a from the user*/
    Scanner input = new Scanner(System.in);
    System.out.println("Enter the value of initial velocity: ");
    u = input.nextFloat();
    System.out.println("Enter the value of acceleration: ");
    a = input.nextFloat();
    
    /*Asking the user if the third parameter is time or displacement*/
    System.out.println("Press 't' or 'T' to enter the value of time; press 's' or 'S' to enter the value of displacement:");
    
    while(true) {
      c = input.next(); 
      if((c.charAt(0) == 't' || c.charAt(0) == 'T') && c.length() == 1) { 
        /*Since the user chose time, take the value of t and calculate velocity using the first formula*/ 
        System.out.println("Enter the value of time: "); 
        t = input.nextFloat(); 
        v = u + a * t; 
        break; 
      } 
      else if((c.charAt(0) == 's' || c.charAt(0) == 'S') && c.length() == 1){ 
        /*Since the user chose displacement, take the value of s and calculate velocity using the second formula*/ 
        System.out.println("Enter the value of displacement: "); 
        s = input.nextFloat(); 
        v = (float) Math.sqrt(u*u + 2*a*s); 
        break; 
      }
      else {
        /*This condition is entered when the user inputs an incorrect character */
        System.out.println("Please enter the correct character.");
      }
    }

    System.out.println("Velocity = " + v);
  }	
}

Output:

Example 1) For, u = 0, a = 10, t = 5,

Enter the value of initial velocity: 
0 
Enter the value of acceleration: 
10 
Press 't' or 'T' to enter the value of time; press 's' or 'S' to enter the value of displacement: 
t 
Enter the value of time: 
5 
Velocity = 50.0

Example 2) For, u = 2.4, a = 5, s = 10,

Enter the value of initial velocity: 
2.4
Enter the value of acceleration:
5
Press 't' or 'T' to enter the value of time; press 's' or 'S' to enter the value of displacement: 
s 
Enter the value of displacement: 
10 
Velocity = 10.283968