Y= A e^αt; which equation is this?

The image shows a pendulum in simple harmonic motion the pendulum starts at a and swing to e

Which best represents the law of conservation of mass ?

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