Marble C, with mass 5.0 g, moves at a speed of 20.0 cm/s. It collides with a second marble, D, with mass 10.0 g. moving at 10.0 cm/s in the same direction. After the collision, marble C continues with a speed of 8.0 cm/s in the
same direction.
a. Sketch the situation, and identify the system. Identify the before and after situations, and set up a coordinate
system.

Often called simply "velocity," this is the velocity of an object at a particular moment in time.

If a star is moving toward earth, it is

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?