Download PHY 101 - Oakton Community College

PHY 101–002
Oakton Community College
Fall 2009
Practice Test 2
1) 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 greater:
A) speed
B) acceleration
C) momentum
D) all of these
E) none of these
2) A bullet is fired from a gun. The speed of the bullet will be about the same as the speed of the recoiling
gun
A) because momentum is conserved
B) because velocity is conserved
C) because both velocity and momentum is conserved
D) if the mass of the bullet equals the mass of the gun
E) none of these
3) A 4 kg ball has a momentum of 12 kg-m/s. What is the ball's speed?
A) 3 m/s
B) 4 m/s
C) 12 m/s
D) 48 m/s
E) none of these
4) Recoil is noticeable if you throw a heavy ball while standing on roller skates. If instead you go through
the motions of throwing a ball but hold onto it, your net recoil will be:
A) zero
B) the same as before
C) small but noticeable
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PHY 101–002
Oakton Community College
Fall 2009
Practice Test 2
5) A 5000 kg freight car moving a 2 m/s runs into a 10000 kg freight car at rest. They couple upon collision
and move away as one body at
A) 2 m/s
B) 1 m/s
C) 2/3 m/s
D) 1/3 m/s
6) A 50 kg sack is lifted 2 m in the same time that a 25 kg sack is lifted 4 m. The power expended in raising
the 50 kg sack compared to the power used to lift the 25 kg sack is
A) twice as much
B) half as much
C) the same
7) A 2 kg mass is held 4 m above the ground. What is the approximate potential energy of the mass with
respect to the ground?
A) 20 J
B) 40 J
C) 60 J
D) 80 J
E) none of these
8) A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has
A) 4 times the kinetic energy
B) 8 times the kinetic energy
C) 12 times the kinetic energy
D) 16 times the kinetic energy
9) A machine puts out 100 watts of power for every 1000 watts put into it. The efficiency of the machine is
A) 10%
B) 50%
C) 90%
D) 110%
E) none of these
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PHY 101–002
Oakton Community College
Fall 2009
Practice Test 2
10) Two 5000 kg freight cars roll toward one another on a level track. One is going 1 m/s and the other is
going 2 m/s. One of them has 2500 J of kinetic energy and the other has 10000 J of kinetic energy. After
they collide and couple, the amount of kinetic energy turned into heat is:
A) 1250 J
B) 2500 J
C) 7500 J
D) 10000 J
E) 11250 J
11) Horses that move with the fastest linear speed on a merry-go-round are located
A) near the center
B) near the outside
C) anywhere because they all move at the same speed
12) The rotational inertia of your leg is greater when your leg is
A) straight
B) bent
C) ... same either way
13) On a balanced see-saw, a boy three times as heavy as his partner sits
A) 1/3 the distance from the fulcrum
B) less than 1/3 the distance from the fulcrum
C) more than 1/3 the distance from the fulcrum
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PHY 101–002
Oakton Community College
Fall 2009
Practice Test 2
14) The center of mass of a human body is located at a point
A) which is fixed, but different for different people
B) that is always directly behind the belly button
C) that changes as a person bends over
D) none of these
15) A flywheel's diameter is twice that of another of the same shape and mass. The larger flywheel's
rotational inertia is
A) 4 times the other's
B) 2 times the other's
C) the same as the other's
D) half the other's
16) According to Newton, doubling the distance between two interacting object
A) divides the gravitational force between them by 2
B) multiplies the gravitational force between them by 2
A) divides the gravitational force between them by 4
B) multiplies the gravitational force between them by 4
17) If the mass of the earth somehow increased with no change in radius, your weight would
A) increase also
B) decrease
C) stay the same
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PHY 101–002
Oakton Community College
Fall 2009
Practice Test 2
18) If your mass, the mass of the earth, and the mass of everything in the solar system were twice as much
as it is now, yet everything stayed the same size, your weight on earth would
A) be the same
B) double
C) quadruple
D) be eight times as much
E) none of these
19) When the distance between two stars decrease to half, the gravitational force between them
A) decreases to one-quarter
B) decreases to one-half
C) increases to twice as much
D) increases to four times as much
E) stays the same
20) The main reason tides exist is that the pull of the moon
A) and sun are in conjunction at high tides and in opposition at low tides
B) is greater on the oceans closer to the moon and less on oceans farther from the moon
C) is greater on the earth because the moon is closer to the earth
D) and the sun on the oceans are in opposite directions
E) none of these
21) A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, the vertical component
of its velocity
A) increases
B) remains unchanged
C) decreases
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PHY 101–002
Oakton Community College
Fall 2009
Practice Test 2
22) A stone is thrown horizontally from the top of a cliff. One second after it has left your hand, its vertical
distance below the point it left your hand is
A) 5 m
B) 10 m
C) 15 m
23) The circular orbit of a satellite orbiting the earth is characterized by a constant
A) speed
B) acceleration
C) radial distance
D) all of these
E) none of these
24) Communications and weather satellites always appear at the same place in the sky. This is because
these satellites are
A) beyond the pull of the earth's gravitational field
B) moving at a speed just short of escape velocity
C) orbiting the earth with a 24 hour period
D) stationary in space
E) none of these
25) From the earth, one satellite appears to overtake another. The faster satellite is
A) higher
B) lower
C) can't say
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