Einstein’s famous formula E = MC2 gives the amount of energy released by the com
ID: 667676 • Letter: E
Question
Einstein’s famous formula E = MC2 gives the amount of energy released by the complete conversion of matter of mass M into energy E. If M represents the mass in kilograms and C represents the speed of light in meters per second (3.0 * 108 m/s), then the result is in the energy unit Joules. It takes 36000 Joules to light a 100 watt light bulb for an hour. Write a Java program that calculates the energy and the number of light bulbs that could be powered by a given mass of matter. Input a double value from the keyboard, and use scientific notation (E notation) and printf statements. Output should look similar to below.
Sample Run:
This mass could provide 9E+14 Joules of energy.
It could power 2.5E+09 100 watt light bulbs for an hour.
Explanation / Answer
/**The java program that prompts the user to enter the mass in the
* kgs and then calculates the energy realsed by the mass
* prints energy and number of bulbs that could power with
* given mass*/
//MassEnergyProgram.java
import java.util.Scanner;
public class MassEnergyProgram
{
//Initialize light speed 3x10 power 8 m/sec
static final double SPEED_OF_LIGHT = 3E8;
//energy required to power 100 watt bulb for 1 hour
static final int ENERTY_PER_100WATTBULB = 36000;
public static void main(String[] args)
{
//Create an instance of Scanner class
Scanner input = new Scanner (System.in);
System.out.println("Enter the mass in kg:");
//read mass value from the user
double mass = input.nextDouble ();
//calculate the energy released for given mass
double energy = mass * SPEED_OF_LIGHT * SPEED_OF_LIGHT;
System.out.println("This mass could provide " + energy+" Jouls of energy");
System.out.println("It could power " + energy / ENERTY_PER_100WATTBULB+
" 100 watt light bulbs for an hour.");
}//end of the main method
}//end of the class
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Sample Output:
Enter the mass in kg:
0.01
This mass could provide 9.0E14 Jouls of energy
It could power 2.5E10 100 watt light bulbs for an hour.
Hope this helps you