Mid- Term Exam Physics
1) A hypothesis is
A) close agreement by competent observers of observations of the same phenomena.
B) a guess that has been tested over and over again and always found to be true.
C) a synthesis of a large collection of information that includes guesses.
D) the long side of a right triangle.
E) an educated guess that has yet to be proven by experiment.
2) To test a scientific hypothesis you would _________
A) find the best result and report only that result.
B) perform any physics experiment and look at the results.
C) use the results of only the experiments that confirm the hypothesis.
D) set up many experiments and look at the results.
E) set up an experiment and look at the results.
3) A runner traveled 15 km east then backtracked 11 km before stopping. The displacement from the original position is
A) 4 km
B) 26 km
C) -4 km
D) -26 km
4) The distance the runner traveled is
A) 4 km B) 26 km
C) -4 km
D) -26 km
5) The velocity of an object is shown on the graph to the right.
What is the acceleration at t = 10 seconds?
A) 2 m/s2 B) 10 m/s2
C) 20 m/s2
D) 40 m/s2
6)
7)
Speed is ________
A) the distance covered per unit time.
B) a measure of how fast something is moving.
C) always measured in terms of a unit of distance divided by
time.
D) all of the above.
E) none of the above.
a unit of
Acceleration is defined as the CHANGE in ______
A) distance divided by the time interval.
B) time it takes to move from one place to another place,
C) velocity divided by the time interval.
D) time it takes to move from one speed to another speed.
E) velocity of an object.
8) The symbol delta  means
A) the final value
C) the original value
B) the change in values
D) the sum of values
9) In the absence of air resistance, objects fall at constant _________
A) distances each successive second,
B) speed.
C) acceleration.
D) velocity.
E) all of the above
10) If you drop a feather and a coin at the same time in a tube filled with air, which will reach the bottom of the
tube first?
A) Neither-they will both reach the bottom at the same time
B) The feather
C) the coin
11) A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point.
During this time the acceleration of the ball is always
A) in the direction of motion.
B) opposite its velocity
C) directed downward.
D) directed upward
12) A ball is thrown straight up. At the top of its path its instantaneous speed is ________
A) about 10 m/s. B) 0
C) about 5 m/s.
D) about 20 m/s.
13) A ball is thrown straight up. At the top of its path its acceleration is _________
A) about -10 m/s2
B) about -50 m/s2
C) about -5 m/s2
D) about -20 m/s2
E) 0
14) Ten seconds after starting from rest, a freely falling object will have a speed of _____________
A) more than 500 m/s
B) 50 m/s.
C) 100 m/s.
D) 10 m/s.
E) 500 m/s
15) When something falls to the ground, it accelerates. This acceleration is called the acceleration due to gravity and is
symbolized by the letter g. What is the value of g on the earth's surface?
A) about 20 m/s2
B) about 50 m/s2
C) 0
D) about 5 m/s2
E) about 10 m/s2
16) A vector is a quantity that has ___________
A) magnitude and time.
B) time and direction.
17) A scalar is a quantity that has
A) direction.
B) color.
__________
C) magnitude.
C) magnitude and direction
D) time
18) In the absence of air friction, the vertical component of a projectile's velocity doesn't change as the projectile moves.
A) sometimes true
B) always false
C) always true
19) In the absence of air friction, the horizontal component of a projectile's velocity doesn't change as the projectile
moves.
A) Sometimes true
B) Always false
C) Always true
20) At the instant a ball is thrown horizontally with a large force, an identical ball is dropped from the same height.
Which ball hits the ground first?
A) The dropped ball
B) The horizontally thrown ball
C) Neither -- they both hit the ground at the same time.
21) In the absence of air resistance, the angle at which a thrown ball will go the farthest is _________
A) 60 degrees. B) 75 degrees.
C) 15 degrees.
D) 45 degrees.
E) 30 degrees
22) What is the resultant of a 4-unit vector and 3-unit vector at right angles to each other?
A) 5 units.
B) 1 unit.
C) 7 units.
D) none of the above
3
4
23) Suppose a small plane can fly at 200 km/h relative to the surrounding air. Suppose also that there is a 40-km/h
tailwind. How fast does the plane's shadow move across the ground?
A) 5 km/h
B) 200 km/h C) 240 km/h D) 40 km/h
E) 160 km/h
(24-26) A projectile is launched with the horizontal and vertical components of velocity as shown.
24) What is the original velocity, vo, of the projectile?
A) 30 m/s
B) 40 m/s
C) 50 m/s
D) 70 m/s.
vo
30 m/s
25) How many seconds will it take for the projectile to reach the ground?
A) 6 s
B) 7 s
C) 8 s
D) 9 s
26) What is the range of the projectile?
A) 160 m
B) 180 m
C) 240 m
40 m/s
D) 360 m
27) The metric unit for force is
A) Meter B) kg C) Newton
D) Watt
28) For every force there is
A) weight
B) a torque
C) an unbalanced force
D) an equal but opposite force
29) An object at rest will remain at rest
A. unless forces are acting on it.
B. unless a net force acts on it
C. unless balanced forces act on it.
30) The acceleration of an object can be found by dividing the net force by the mass.
A) Newton's First Law
B) Newton's Second Law
C) Newton's Third Law
31) One object has twice as much mass as another object. The first object also has twice as much __________
A) velocity.
B) inertia.
C) energy.
D) gravitational acceleration.
4
E) all of the above
3
32) A student hangs different masses from a spring and
measures how much the spring stretches. She
recorded the extension and graphed the extension vs.
the Spring Force. She recognizes that the spring force
is equal to the weight suspended by the spring.
Approximately how many meters would the spring
stretch when a 0.10 kg mass is hung from it?
A) 0.03 m
B) 0.15 m
C) 1.8 m
D) 2.2 m
2
1
33) Compared to its weight on earth, a 10 kg object on the moon will weigh ____________
A) more.
B) less.
C) the same
34) Compared to its mass on earth, the mass of a 10 kg object on the moon is ____________
A) more.
B) less
C) the same
35) The mass of a dog that weighs 100 N is about _____
A) 1 kg.
B) 10 kg
C) 1000 kg.
D) 100 kg.
E) none of the above
36) A 10 N force and a 30 N force act on an object in opposite directions. What is the net force on the object?
A) 10 N
B) 30 N
C ) 40 N
D) 20 N E) none of the above
37) If the mass of the object in the previous problem (#36) was 10.0 kg, what would be its acceleration?
A. 2 m/s2
B. 3 m/s2
C. 4 m/s2
D. 5 m/s2
38) Friction is a force that always acts ___________
A) opposite to the object's motion.
B) perpendicular to the object's motion.
C) in the same direction as the object's motion.
39) When an object reaches terminal velocity, its acceleration is _______
A) 0 m/s2
B) -9.8 m/s2
C) ½ g
D) – ½ g
40) In order to initiate motion, this must be overcome.
A) energy
B) kinetic friction C) static friction
E) variable
D) momentum
41) A 5 kg box is being pushed across a horizontal floor. If the coefficient of kinetic friction is 0.2, how large is the
frictional force?
A) 0.2 N
B) 1.0 N
C) 10.0N
D) 20.0 N
42) A girl pulls on a 10 kg wagon with a constant force of 30 N. What is the wagon's acceleration?
A) 3.0 m/s2
B) 10 m/s2
C) O.3 m/s2
D) 30 m/s2
B) 300 m/s2
43) An airplane flying due north at 110 mph experiences a wind blowing due east at 30
mph. What is the resultant velocity of the airplane?
A) 114 mph B) 140 mph
C) 80 mph
D) 108 mph
E) 98 mph
110 mph
30 mph
44) A player catches a ball. Consider the action force to be the impact of the ban against the player's glove. What is the
reaction to this force?
A) The muscular effort in the player's arms
B) The force the glove exerts on the ban
C) Friction of the ground against the player's shoes
D) The player's grip on the glove
E) none of the above
45)
A 5000 kg truck moves east at 15 m/s. A 1000 kg car moves west at 20 m/s. What is the magnitude of the
momentum of the truck/car system?
A) 55000 kg·m/s
B) 95000 kg·m/s
C) 75000 kg·m/s
D) 20000 kg·m/s
46) According to Newton's third law, if you push gently on something, it will push______
A) gently on you.
B) gently on something else
C) on you only if you aren't moving.
D) on something only under the right conditions.
47) As a 50 kg woman sits on the floor, the floor exerts a force on her of
A) 50 N
B) 500 N
C) 5 N
D) zero
48) The momentum change of an object is equal to the ___________
A) object's mass times the force acting on it.
B) force acting on it times its velocity.
C) velocity change of the object.
D) force acting on it.
E) Impulse acting on it.
49) Two objects, A and B, have the same size and shape, but A is twice as heavy as B. When they are dropped
simultaneously from a tower, they reach the ground at the same time, but A has a higher
A) speed
B) momentum.
C) acceleration.
D) all of the above
E) none of the above
50) Which has more momentum, a large truck moving at 30 miles per hour or a small truck moving at 30 miles per hour?
A) Both have the same momentum.
B) The large truck
C) The small truck
51) The force that accelerates a rocket into outer space is exerted on the rocket by the ______
A) rocket's wings.
B) Earth's gravity.
C) atmospheric pressure.
D) exhaust gases.
E) none of the above
52) The reason padded dashboards are used in cars is that they _______
A) increase the force of impact in a collision.
B) increase the time of impact in a collision.
C) look nice and feel good.
D) decrease the momentum of a collision.
E) decrease the impulse in a collision.
53) Momentum of a system is conserved only when _________
A) there are no forces acting on the system .
B) the system is not moving.
C) there are no internal forces acting on the system.
D) the system has zero momentum.
E) there is no net external force acting on the system.
54) A collision is considered elastic if _______
A) the objects stick together after the collision
C) energy is not conserved
B) momentum is not conserved
D) both energy and momentum are conserved
55) A collision is considered totally inelastic if
A) the objects stick together after the collision
C) energy is not conserved
B) momentum is not conserved
D) both energy and momentum are conserved
56) A cannon recoils from launching a cannonball. The speed of the cannon’s recoil is small because the
A) cannon has far more mass than the cannonball.
B) momentum of the cannon is unchanged.
C) impulse on the cannon is less than the impulse on the cannonball.
D) force against the cannon is relatively small.
E) none of the above
57) A 1 kg chunk of putty moving at 6 m/s collides with and sticks to a 5 kg bowling ball that is initially at rest. The
bowling ball with its putty passenger will then be set in motion with a final velocity of _______
A) 1 m/s.
B) 2 m/s.
C) 3 m/s.
D) 4 m/s.
58) A golfer hits a golf ball with a force of 60 N. The club is in contact with the ball for 0.04 s. If the mass of the ball was
0.05 kg, how fast was the ball moving after it was hit?
A) 0.12 m/s
B) 75 m/s
C) 48 m/s
D) 54 m/s
59) A freight train rolls along a track with considerable momentum. If it were to roll at the same speed but had
twice as much mass, its momentum would be
A) doubled
B) unchanged
C) quadrupled
D) zero
60) In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion.
Doing this reduces the force of impact on the player's hand principally because
A) the velocity of the hand is reduced
B) the time of impact is increased.
C) the momentum of impact is reduced.
D) the time of impact is decreased
(61-63) In the following questions, refer to the position-time graph above and consider the following time intervals:
A: from t = 0.00 seconds – 3.00 seconds
B: from t = 5.00 seconds – 7.00 seconds
C: from t = 9.00 seconds – 11.00 seconds
61) In which segment(s) was the object at rest?
a) A
b) B
c) C
d) A & B
e) B & C
62) In which segment(s) was the object accelerating?
a) A
b) B
c) C
d) A & B
e) B & C
63) In which segment(s) was the object moving with a constant velocity?
a) A
b) B
c) C
d) A & B
e) B & C
64) For "work" to be done on an object, the applied force must be _______ the displacement.
A) in the same direction as B) perpendicular to
C) opposite to
D) parallel to
65) Power is defined as the _____________
A) force on an object divided by the time the force acts.
B) force on an object times the distance the object moves
C) work done times the time taken to do that work.
D) work done on an object divided by the time taken to do the work
66) The unit of power is
A) Joule.
B) Newton.
C) second
D) Watt
E) meter
67) Gravitational Potential energy is the energy an object has because of its ___________
A) height above a reference point.
B) temperature,
C) speed,
D) density,
E) size.
68) A job is done slowly, and an identical job is done quickly. Both jobs require the same amount of work but different
amounts of
A) energy
B) power
C) both A and B
D) none of the above
69) The smallest of the fundamental forces of nature is the ____________force
A) electromagnetic
B) weak
C) strong nuclear
D) gravitational
E) kinematic
70) A 5 kg cannonball is loaded into a 200 kg cannon that is at rest. When fired, the
cannon ball has a velocity of 20 m/s, what is the recoil speed of the cannon?
A) 0.5 m/s
B) 2 m/s
C) 4 m/s
D) 10 m/s
71) A 10 N object moves at 1 m/s. Its kinetic energy is ________
A) 0.5 J.
B) more than 10
C) 10 J
D) 1 J
72) It takes 40 J of work to push a large box 4 m across a floor. Assuming the push is in the same direction as the move,
what is the magnitude of the force on the box?
A) 160 N
B) 4 N
C) 40 N
D) 10 N
E) none of the above
73) After climbing a ladder, a man of mass 65 kg has a potential energy of 7500 J How high is he?
A) 26.7 m
B) 32.5 m
C) 115 m
D) 11.53 m
74) In which set of masses below, separated by the given distances, is the gravitational force of attraction the greatest?
A)
B)
½m
½m
m
m
½d
d
C)
D)
2m
m
2
2d
4m
m
4
3d
75) Which has greater kinetic energy, a car traveling at 30 km/h or a half-as-massive car traveling at 60 km/h?
A) both have the same kinetic energy.
B) The 30 km/h car
C) The 60 km/h car
Physics First Semester Exam 2011 Key
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