If you want to do an experiment to see how speed affects a cart’s kinetic energy, what should you do?

a)keep everything the same except the kinetic energy of the cart.
b)keep everything the same except the speed of the cart.
c) none of the above

*i am stuck on this because i’m not sure if the answer c since shouldn’t have to do something with height? *

One soccer player (a) is moving at 4 km/h when she kicks the ball while another soccer player (b) is moving at 8 km/h. what statement accurately compares their kinetic energy if they have the same mass? a) both soccer players have the same kinetic energy. b) player b has twice the kinetic energy of player a. c) player b has four times the kinetic energy of player a. d) their kinetic energy can't be compared without knowing their mass.