Review of Energy: Kinetic, Gravitational Potential, Spring Potential, and Energy Wasted by Friction

In this physics tutorial, we review types of energy and work an example in which we find that distance that a spring compresses when struck by a moving block. Initially, the block has both gravitational potential energy (mgh) and kinetic energy (½ mv^2). On its way down a rough ramp, energy is wasted (converted to heat and sound) in the amount given by the product of kinetic friction force and distance. Friction is doing negative work here since the direction of the blocks displacement (downhill) is opposite the direction of the kinetic friction force (uphill). The remaining mechanical energy in the system (the energy that remains in the system after the block has finished sliding down the ramp) is converted to spring potential energy (½ k(∆x)^2) in which ∆x is the distance by which a spring is compressed and k is the spring constant or force constant (Hooke's Law constant) of a spring.