CID# _________________ Quiz #6
Physics 121 Friday, May 23, 2008
1. The total momentum of an isolated system (a) never changes, (b) changes only if non-conservative forces
act within the system, (c) changes whenever an external force acts on the system, (d) is often variable.2. The total momentum of an isolated system (a) is the same in all inertial reference frames, (b) is always zero,
(c) depends upon the reference frame in which the system is described, (d) can never be determined.3. A body with a very small mass, traveling at a high speed, bounces normally, with virtually no loss of kinetic
energy (a so-called "elastic collision"), off an initially stationary, very massive body. Immediately after the
collision the momentum of the massive body is about equal to (a) zero, (b) the initial momentum of the low
mass body, (c) minus the initial momentum of the low mass body, (d) twice the the initial momentum of the
low mass body, (e) minus twice the initial momentum of the low mass body.4. When a gun is fired (a) the bullet carries off most of the resultant kinetic energy and momentum, (b) the
bullet carries off most of the kinetic energy. The gun and the bullet acquire equal quantities of momentum
(comparing magnitudes), (c) the bullet carries off most of the kinetic energy, the gun acquires most of the
momentum, (d) the bullet and the gun acquire both equal quantities of kinetic energy and momentum, (e)
the bullet and the gun acquire equal quantities of kinetic energy, but the bullet acquires most of the
momentum, (f) the bullet and the gun acquire equal quantities of kinetic energy; the gun acquires most of
the momentum, (g) the gun acquires most of the kinetic energy, the bullet acquires most of the momentum,
(h) the gun acquires most of the kinetic energy, but the momenta of the gun and bullet are equal, (i) the gun
carries most of the kinetic energy and most of the momentum.5. Which of the following is a momentum unit? (a) J s, (b) kg m/s, (c) kg m2/s2, (d) kg m/s2, (e) kg m2/s.