A bicyclist at the top of a hit begins to coast without pedaling. The bicycle speeds up as it descends to the bottom of the hill and then slows down as it continues up a second, where it stops. Which of these sequences best describes the energy change of the bicycle from the top of the hill until it stops?

A. potential - kinetic-kinetic

B. Kinetic -potential -potential

C. Kinetic -potential -Kinetic

D. potent - Kinetic -potential

Cyclotrons are widely used in nuclear medicine for producing short-lived radioactive isotopes. these cyclotrons typically accelerate h- (the hydride ion, which has one proton and two electrons) to an energy of 5 mev to 20 mev. this ion has a mass very close to that of a proton because the electron mass is negligible—about 1 2000 of the proton’s mass. a typical magnetic field in such cyclotrons is 1.9 t. (a) what is the speed of a 5.0-mev h-? (b) if the h- has energy 5.0 mev and b = 1.9 t, what is the radius of this ion’s circular orbit?