Lesson: Conservation of Energy
In this lesson, we will learn how to calculate the change in the kinetic energy or gravitational potential energy of an object when work is done on it.
Sample Question Videos
Worksheet: 25 Questions • 2 Videos
Ignoring details associated with friction, extra forces exerted by arm and leg muscles, and other factors, we can consider a pole vault as the conversion of an athlete’s running kinetic energy to gravitational potential energy. If an athlete is to lift his body 4.8 m during a vault, what speed must he have when he plants his pole?
A sprinter of mass 60 kg accelerates from 2.00 m/s to 8.00 m/s over a 25.0-m-distance of racetrack. The sprinter is running into the wind, which exerts an average force of 30.0 N. What average force does the sprinter exert on the track?
When the force acting on an object is parallel to the direction of the motion of the center of mass, the mechanical energy . When the force acting on an object is antiparallel to the direction of the center of mass, the mechanical energy .