Question

A child is on a pogo stick. At the top of her jump, her kinetic energy (KE) = 0 J, her gravitational potential energy (GPE) = 100 J, and the potential energy in the spring (SPE) = 0 J. At the bottom of the jump, immediately before the child jumps again, what do KE, GPE, and SPE equal? (Assume a closed system.

A) KE = 0 J, GPE = 100 J, and SPE = 0 J
B) KE = 50 J, GPE = 0 J, and SPE = 50 J
C) KE = 100 J, GPE = 0 J, and SPE = 0 J
D) KE = 0 J, GPE = 0 J, and SPE = 100 J

Answer 1

There would be 0 Potential energy, which eliminates A. There would be Spring energy, which eliminates C. So B and D are your 2 choices. Since the child is not moving just before the jump, there would be 0 Kinetic energy. So D.