Physics 223 - Fall 2011 - Quiz #2
Name:____________________________________
**Indicate the correct answer from the choices provided with each question. In addition, you must justify your
selection of an answer. You may show your mathematical work, provide a clear definition, or eliminate the
incorrect answers. Only partial credit will be given if a clear justification is not provided.
Us the following information to answer the 1a and 1b: s, s0, r and x have units of length, t has
units of time, v has units of velocity, g and a have units of acceleration, and k is
dimensionless.
1a. Is the following equation dimensionally correct?
1b. Is the following equation dimensionally correct?
2. The graph to the right shows the velocity as a function of
time for an object moving in a straight line. Which of the
following graphs below shows the corresponding
displacement as a function of time for the same time interval?
3. An object was suspended in a fixed place (y = 0) and then allowed to drop in a free fall.
Taking up as the positive vertical direction, which of the following graphs correctly represents
its vertical motion as displacement vs. time?
4. A mass attached to a spring bounces up and down as indicated in the position vs. time plot
below. At point P, the mass has
y
1. positive velocity and positive acceleration.
2. positive velocity and negative acceleration.
3. positive velocity and zero acceleration.
4. negative velocity and positive acceleration.
5. negative velocity and negative acceleration.
6. negative velocity and zero acceleration.
7. zero velocity but is accelerating (positively or negatively).
8. zero velocity and zero acceleration.
5. A baseball catcher throws a ball vertically upwards and catches it in the same spot when it
returns to his mitt. At what point in the ball's path does it experience zero velocity and nonzero acceleration at the same time?
a) midway on the way up
b) at the top of its trajectory
c) the instant it leaves the catcher's hand
d) the instant before it arrives in the catcher's mitt
6. Two objects of different mass are released simultaneously from the top of a 20m tower and
fall to the ground. If air resistance is negligible, then which of the following statements best
applies?
a) The greater mass hits the ground first
b) Both objects hit the ground together
c) The smaller mass hits the ground first
d) No conclusion can be made with the information given
7. When an object is traveling upward it:
a) is still accelerating downward
b) is accelerating upward
c) traveling faster than the acceleration due to gravity
d) has a very large density