Sample Midterm 1 Exam

PHYS 250 Sample Midterm 1
1. Identify the forces acting on a cannon shell that is flying through the air.
A. Force of the cannon, drag, gravity
B. Gravity, inertia
C. Force of the cannon, gravity
D. Force of the cannon, drag
E. Drag, gravity
2. A 0.25 kg block slides across a table with a constant velocity of 5 m/s. The net force exerted on
the block is
A. 0 N B. 5 N C. 2.5 N
D. 20 N E. Cannot be determined
from information given
3. In the lab "Motion of a Freely Falling Body" you were asked to graph the position of a falling
object as a funtion of the time and as a function of the time squared. Which graph best
represents the position of a falling object (that is accelerating at a constant rate) versus time
squared? (For this question take the positive y-direction to be up).
A. V
B. I
C. II
D. IV
E. III
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PHYS 250 Sample Midterm 1
4. A 2-kg object is falling downward with its speed increasing at a rate of 8 m/s per second. We
conjecture that there must be some other force acting on the object in addition to the downward
pull of gravity. What can we say about this other force?
A. It has a magnitude of 2 N and points in the downward direction.
B. It has a magnitude of 16 N and points in the upward direction.
C. It has a magnitude of 36 N and points in the upward direction.
D. It has a magnitude of 4 N and points in the upward direction.
E. It has a magnitude of 20 N and points in the downward direction.
5. A force of 120 N is applied to an object whose mass is 30 kg. The object's acceleration is:
A. 4.0 m/s 2 .
B. 0.25 m/s 2 .
C. 150 m/s 2 .
D. 3600 m/s 2 .
6. Abby throws a ball straight up and times it. She sees that the ball goes by the top of a flagpole
after 0.60 s and returns to the level of the top of the pole after a total elapsed time of 4.20 s.
What was the speed of the ball at launch?
A. 33.9 m/s
B. 11.3 m/s
C. 23.5m/s
D. 45.2 m/s
7. A ball is thrown straight up into the air. At the highest point in its trajectory, the net force acting on
it is:
A. equal to its weight.
B. less than its weight, but not zero newtons.
C. 9.8 newtons.
D. greater than its weight.
E. zero newtons.
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PHYS 250 Sample Midterm 1
8.
v
i
v
f
An airplane initially heading north makes a 90° turn east such that its
speed remains constant. The plane’s velocity vector before and after
the turn are shown at left. Which of the options below represent the
plane’s change in velocity vector?
A. B. C. D. E.
9. Find the magnitude and direction of the net force on the object in each of the free-body diagrams
in the figure below.
A. (a) 30 N to the right; (b) 10 N to the right; (c) 18 N upward
B. (a) 40 N to the left; (b) zero; (c) 18 N downward
C. (a) 30 N to the right; (b) zero; (c) 18 N upward
D. (a) 40 N to the left; (b) 10 N to the right; (c) 18 N downward
E. (a) 30 N to the right; (b) zero; (c) 18 N downward
10. Find the x- and y-components of a position vector, r , with a magnitude of r = 77 m and
an angle with respect to the x-axis of 25°.
A. (69.8 m, 32.5 m)
B. (-10.2 m, 76.3 m)
C. (69.8 m, -10.2 m)
D. (76.3 m, -10.2 m)
E. (32.5 m, 69.8 m)
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PHYS 250 Sample Midterm 1
11. A boy throws a ball at an initial velocity of 26 m/s at an angle of 20o above the horizontal. How
high above the projection point is the ball after 1.4 s?
A. 2.8 m
B. 1.4 m
C. 8.2 m
D. 24 m
E. 23 m
12. You heave a baseball straight upwards such that it leaves your hand with a speed of 20 m/s
(approximately 45 mph). If we neglect the effects of air resistance, approximately how long does
it take the baseball to return to your hand?
A. 4 s
B. 3 s
C. 5 s
D. 1 s
E. 2 s
13. A bullet is fired from ground level with a speed of 250 m/s at an angle 35o above the horizontal at
a location where g = 10.0 m/s 2 . How long does it take before the bullet hits the ground?
A. 41.0 s
B. 28.7 s
C. 20.5 s
D. 14.3 s
E. 1 35.0
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PHYS 250 Sample Midterm 1
14. In a game of three-way tug-of-war, Team Agathon and Team Boomer each pull as shown in the
free-body diagram below. Determine the appropriate components of the force exerted by the
third team, Team Caprica, if there is to be a tie (i.e., no team successfully moves the knot in the
middle.) Each grid unit represents one newton.
y
F
Agathon
F
Boomer
x
F x yˆ
A.
Caprica
7N ˆ
2N
B.
Caprica
3N ˆ
1N
C.
Caprica
2N ˆ
7N
D.
FCaprica
9Nxˆ
E.
Caprica
7N ˆ2N
F x yˆ
F x yˆ
F x yˆ
15.
v constant
m
T
A heavy block with a mass m is
being pulled up a smooth,
frictionless incline by a rope such
that the block moves up the ramp
at a constant velocity. What must
the tension in the rope be?
A. mg tan
B. mg sin
C. mg
D. mg cos
E. It depends upon how fast the block is being pulled.
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PHYS 250 Sample Midterm 1
16. A 20-ton truck collides with a 1500-lb car and causes a lot of damage to the car. We can
definitely say that:
A. The force exerted on the truck (by the car) is less than the force exerted on the car (by the
truck).
B. The force exerted on the truck (by the car) is equal to the force exerted on the car (by the
truck).
C. The truck did not slow down during the collision.
D. The force exerted on the truck (by the car) is greater than the force exerted on the car (by
the truck).
E. The car did not slow down during the collision.
17. A 0.5-kg glider floats at rest on a cushion of air above an air track. (The glider/track system is
essentially frictionless.) Lauren pulls a string connected to the right side of the glider with a
constant force of 10 N. Simultaneously, Paula pulls a string connected to the left side of the glider
with a constant force of 6 N. What happens to the glider?
A. It moves to the right, speeding up at a constant rate of 32 m/s per second.
B. It moves to the right, slowing down at a constant rate of 12 m/s per second.
C. It moves to the right, speeding up at a constant rate of 20 m/s per second.
D. It moves to the right, speeding up at a constant rate of 8 m/s per second.
E. It does not move at all.
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PHYS 250 Sample Midterm 1
18. A 1-kg block rests on a horizontal, frictionless table and is fastened to a spring of negligible mass,
which is mounted to the wall. The spring has a spring constant of 600 N/m. The block is pushed 3
cm toward the wall (thus compressing the spring) and then released.
1 kg
(system at rest)
1 kg
(spring compressed )
Which of the following show a correct free-body diagram for the block at the instant just after it is
released?
A.
N B.
table on block
N C.
table on block
N table on block
f table on block F
spring on block
W earth on block
F
W spring on block
earth on block
F block on spring F
spring on block
W earth on block
D.
N E.
table on block
F block on spring
N table on block
F block on spring F
spring on block
W earth on block
W earth on block
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PHYS 250 Sample Midterm 1
19. The position versus time graph below represents the motion of an object moving in a straight line.
12
position (centimeters)
10
8
6
4
2
0
2
4
1 2 3 4 5 6
time (seconds)
7 8
What is the object's instantaneous velocity at t = 3.0 s?
A. 4.00 cm/s
B. 0.00 cm/s
C. 8.00 cm/s
D. 3.00 cm/s
E. 1.33 cm/s
20. An object moves, pulling a paper tape through a ticker timer which records a dot on the paper at
regular time intervals. What can you determine from the object's motion based on the following
ticker tape? (To aid in making your determination, the paper tape has regularly spaced ruled
marks printed on it as well.)
A. The object had a constant acceleration for the duration of the recording.
B. The object had a constant position for the duration of the recording.
C. The object had a constant velocity for the duration of the recording.
D. The object moved the same distance during each time interval recorded.
E. None of the above statements are true.
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