Download Atwood Machine (AM)

Phy 121L/131L
Pre-Lab: Atwood Machine
Name:
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Choose the best answer. Refer to the lab manual for definitions of the variables used below.
(10 pts total)
In this lab, we will take measurements holding the total mass, m1 + m2, constant (Part A), and
plot net force vs. acceleration (Fnet vs. a). The data should be well fit by a straight line.
1. What are the (SI) units of the slope of the plot? [1 pt]
a. kg m/s2
b. N/m
c. kg
d. 1/kg
2. What are the (SI) units of the y-intercept of the plot?
a. N
b. m/s2
c. N/m
[1 pt]
d. kg
3. If our data is described by “A Simplified Theory” (neglecting pulley inertia and friction),
what should the slope of the plot be equal to?
[1 pt]
a. Fnet
b. m1 – m2
c. m1 + m2
d. m1 + m2 + mp
4. If our data is described by “A Simplified Theory” (neglecting pulley inertia and friction),
what should the y-intercept of the plot be equal to?
[1 pt]
a. Fnet
b. f
c. mp
d. 0
5. If our data is described by “A Better Theory” (includes pulley inertia and friction), what
should the slope of the plot be equal to?
[1 pt]
a. Fnet
b. m1 – m2
c. m1 + m2
d. m1 + m2 + mp
6. If our data is described by “A Better Theory” (includes pulley inertia and friction), what
should the y-intercept of the plot be equal to?
[1 pt]
a. Fnet
b. f
c. mp
d. 0
7. If our data is described by “A Better Theory” (includes pulley inertia and friction), within
uncertainty, should the y-intercept of the plot be positive, negative, or zero?
[1 pt]
a. positive
b. negative
c. 0 (zero)
8. If there is no friction in the pulley system, what is the net force, Fnet, equal to?
[1 pt]
a. f
b. (m1 + m2)g
c. (m1 – m2)g
d. None of these choices.
9. According to Newton’s 2nd Law, the acceleration of a system is _______________
proportional to the total mass of the system and _______________ proportional to the net
force acting on the system.
[1 pt]
a. directly … inversely
b. inversely … directly
c. Neither a or b are correct.
10. In this lab, the computer uses a laser-gate system to determine the speed, v, of the perimeter
of the wheel, as a function of the time, t. The computer then plots the speed vs. time (v vs. t).
What is the slope of this plot equal to? [1 pt]
a. acceleration
b. initial velocity
c. time for m1 to fall
d. None of these.
CSU Pomona
10/15/08
Dr. Julie J. Nazareth