A child is riding downhill in a wagon with a combined mass of 28 kg. Suppose the wagon’s speed increases from 2.4 m/s to 3.7 m/s, and the kinetic energy therefore increases by 110 J. What is a likely source of this change in kinetic energy? *
A) gravity
B) pushed by a friend or parent
C) gaining kinetic energy from the initial kinetic energy
D) converted from the potential energy of being higher on the hill

Acentrifuge in a medical laboratory rotates at an angular speed of 3,700 rev/min. when switched off, it rotates through 54.0 revolutions before coming to rest. find the constant angular acceleration (in rad/s2) of the centrifuge. your response is within 10% of the correct value. this may be due to roundoff error, or you could have a mistake in your calculation. carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. rad/s2