A spring with spring constant 40 N/m is compressed 0.1 m past its natural length. A mass of 0.5 kg is attached to the spring.
a. What is the elastic potential energy stored in the spring? b. the spring is released. what is the speed of the mass as it reaches the natural length of the spring?

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final