Download Quiz #2 - Patricia Wrean

Ph 150 – Quiz #2
October 24, 2003
Instructor: Patricia Wrean
Name: _______________________
Read each question carefully and show all of your work. Your method of solution must
be clearly presented and valid in order to obtain full marks for each question.
Total: 40 points
1. Perform the following unit conversions, showing all work:
(8 points)
a. 8200 µg/ns → SI base units
___________________________
b. 0.040 km/day2 → cm/hour2
___________________________
c. 3.18 × 1012 m3 → Gm3
___________________________
d. 0.87 g/cm3 → SI base units
___________________________
Ph150
Quiz #2
Page 2
2. Draw the free-body diagrams for the following objects, ignoring air resistance.
(10 points)
a. A person is standing in an elevator which is moving downwards at constant
velocity.
b. A wooden crate is being pushed to the left by a horizontal force over a smooth
(frictionless) floor.
c. A car is sliding down an icy (frictionless) hill.
d. A book is being held stationary against a wall by a horizontal force.
Which of the above blocks are in equilibrium?
______________
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Quiz #2
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3. Are the following objects in equilibrium? If not, sketch (roughly) the direction of the
unbalanced force.
(4 points)
120 N
a.
Equilibrium? ______
120 N
40 N
b.
Equilibrium? ______
40 N
80 N
80 N
4. Fill in the remaining force or forces (include both magnitude and direction) for these
objects to be at rest.
(4 points)
a.
2N
5N
10 N
4N
b.
40 N
50 N
5. Which of the following are vectors or scalars? Write “V” for vector, “S” for scalar,
and leave it blank if it’s neither a vector or a scalar.
(4 points)
a.
b.
c.
d.
southeast
3.2 m due south
43 N at 43° N of E
3 hours
_________
_________
_________
_________
e.
f.
g.
h.
velocity
force
volume
mass
_________
_________
_________
_________
Ph150
Quiz #2
Page 4
6. Spaceman Spiff, who weighs 730 N on Earth, travels to Jupiter’s largest moon,
Ganymede. He measures the gravitational field strength gG to be 1.46 N/kg.
Calculate Spiff’s mass and weight on Ganymede. What percentage of Earth’s
gravitational field does Ganymede have?
(5 points)
7. A dog is pulling a sled across a level field at constant velocity. The mass of the sled is
75 kg. The rope connecting the dog and sled is perfectly horizontal, and the
magnitude of the tension force is 320 N. Find both the friction force and the normal
force being exerted on the sled.
(5 points)