An engine is used to pull a train of two cars out of a mine. The floor slopes upward at an angle of 30°. Each car has a mass of 10^4 Kg and normally travels without friction on the tracks. The engine can exert a maximum force of 1.5x10^5 N on car A. If the engineer again throttles back so that the force exerted by the engine on car A decreases at the constant rate of 3 N per second, how long before the train stoprs moving up the track? Assume the original speed was 3 m/s

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?