Kinetic energy is
a. the form of energy that actually does work.
b. movement of ions or electrons.
c. energy that flows between objects with different temperatures.
d. stored energy that could do work but is not doing so.
e. energy that moves in waves.

Free runners jump long distances and land on the ground or a wall. how do they apply newton’s second law to lessen the force of impact?

World class speed skaters can skate a 3,000-m course in about 4 minutes.what is their average speed for this course? a. 12.5 m/sb. 1.33 m/sc. 1.25 m/sd. 13.3 m/s

A1-lb collar is attached to a spring and slides without friction along a circular rod in a vertical plane. the spring has an undeformed length of 5 in. and a constant k =25 lb/ft. knowing that the collar is released from being held at a determine, the speed of the collar and the normal force between the collar and the rod as the collar passes through b.