In which situations is work being done? Hannah leans against her locker, but it doesn’t move.

Andy’s car rolls down a hill with the engine off.

A wind turbine stands still on a sunny, windless day.

A balloon expands as it is heated by the sun.

James pedals a stationary exercise cycle that doesn’t move.

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?

Suppose that two objects attract each other with a gravitational force of 16 units. if the distance between the two objects is double, what is the new force of attraction between the two objects?

Aipal measures a circuit at 1.2 a and 24 . using ohm’s law, what can he calculate for the circuit?