Download Quiz 3 - People Server at UNCW

PHY 101 Quiz #3
Name __________________________
Instructions:
1. Do all of your work on this sheet.
2. Show all of your steps in problems for full credit.
3. Be clear and neat in your work. Any illegible work, or
scribbling in the margins, will not be graded.
4. Place your answers in a box.
5. If you need more space, you may use the back of the
page and write On back in the problem space.
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1. Multiple Guess (3 pts) Find the answer which best fits the
question and write it in the space provided.
a. The measure of inertia of a body is given by
a) g. b) the apparent weight c) the mass d) the force
e) None of these.
_____
b. In the absence of a net force, an object will always
a) be at rest. b) be accelerated.
c) be in motion with a constant non-zero velocity.
d) None of the above.
_____
c. The unit “Newton” is given in base units by
a) kg m/s b) kg m /s2 c) kg m2/s d) kg2 m/s
e) None of these
Score _____
3. Problems (12 pts)
a. An 1100 kg car stuck in mud is pulled out using a force of
7560 N due north. However, the mud resists with a force
of 7340 N due south. What is the acceleration of the car?
b. A 5.00 kg block hangs on a rope as shown. Draw the
forces on the block and find the tension in the rope.
c. A 95.0 kg person stands on a scale in an elevator. What is
the apparent weight if the elevator is decelerating at 1.80
m/s2?
_____
2. Newton's Laws of Motion (5 pts)
a. State Newton's First Law of Motion.
d. (3 pts) Two forces act on a 5.0 kg block as shown below.
The magnitudes of the forces are F1  15.0N and
F2  20.0 N. What is the horizontal acceleration of the
block?
b. The two boxes below are being pushed across a horizontal
frictionless surface. Carefully draw and label all of the
forces acting on the 62 kg box.
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Bonus: Two forces act on a moving object that has a mass of
27 kg. One has a magnitude of 12 N and points due south,
while the other has a magnitude of 17 N and points due west.
What is the magnitude of the acceleration of the object?
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Constants M Moon  7.35 1022 kg, M Earth  5.98 1024 kg,
REarth  6.38  106 m, G  6.67  10 11 Nm2/kg2 ,
Earth-Moon Dist = 3.85  108 m
f. (3 pts) A person weighs 540 N on Earth. What will the
person weigh on the moon?