Answer to Question #212546 in Physics for Yang

Question

1. A dropped ball bounces to one-half its original height. Discuss the energy transformations that take place. 
2. What is the physical meaning of a non-conservative force?

Answer 1

1. The potential energy if this ball converts into kinetic energy, which is maximum when the ball reaches the ground. As the ball rebounds, some part of its kinetic energy becomes thermal energy and/or energy of deformation. The left kinetic energy converts into the final potential energy.

2. The force is non-conservative if its work depends on the trajectory. The total mechanical energy of a system is not conserved when the system is subjected to the action of non-conservative forces. Such forces (like the force of friction or drag force) cause dissipation of energy.