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Physics 2414
Midterm #1 – Spring 2005
Version A
Multiple Choice (6 pts each)
1. I decide to race you in a drag race. I get in an old Ford Pinto and you get in a new
Camaro. We both start from rest and race for one quarter mile. My Pinto can only
accelerate at half the rate as your Camaro. How much longer does it take for me to
finish the race than you?
A) 2 times longer.
B) 2 times as long.
C) 2 2 times longer.
D) 4 times as long.
E) Can only be determined if we know the values of the acceleration.
2. A ball is thrown vertically straight upward from the surface of the earth. Consider the
following quantities: (1) the speed of the ball; (2) the velocity of the ball; (3) the
acceleration of the ball. Which of these is (are) zero when the ball has reached the
maximum height?
A)
B)
C)
D)
E)
1 only
1 and 2
1, 2, and 3
2 only
1 and 3
3) The surface area of a sphere is increased by 12%. The percentage increase of the
volume of the sphere is,
a) 36%
b) 24%
c) 12%
d) 16%
e) 19%
4) Which velocity vs. time graph corresponds to the following graph of position
verses time
A.
B.
D.
E.
C.
5)
6)
5) Can an object's velocity change direction when its acceleration is constant?
A. No, this is not possible because it is always speeding up.
B. No, this is not possible because it is always speeding up or always slowing
down, but it can never turn around.
C. Yes, this is possible, and a rock thrown straight up is an example.
D. Yes, this is possible, and a car that starts from rest, speeds up, slows to a stop,
and then backs up is an example.
E. none of the above.
6) A person standing at the edge of a cliff throws one ball straight up and another
ball straight down. Both balls have the same initial speed. Neglecting air
resistance, the ball that hits the ground below the cliff with the greater speed is the
one initially thrown:
A.
B.
C.
D.
E.
upward
they both have the same speed when they hit the ground.
downward
impossible to tell because they hit at different times
none of these
7) To be dimensionally consistent, velocity [L/T], force [ML/T 2 ], mass [M], and length
[L] must be related as follows:
a.
b.
c.
d.
e.
Velocity squared ~ force length/mass
Velocity squared ~ force mass/length
Velocity squared ~ mass length/force
Velocity squared ~ force mass/length2
Velocity squared ~ mass /force
8) The length 4.221 cm is added to 0.01 cm. The appropriately rounded sum is, in cm,
a) 4.22
b) 4.2301
c) 4.23
d) 4.2
e) 4.21
9) A large massive rock is in contact with the ground surface that is a flat surface on the
earth. Draw a force diagram for the rock and the earth. Which of the following statements
is true?
a) The gravitational force on the rock due to the earth and the gravitational force on the
earth due to the rock are action-reaction pairs.
b) The gravitational force on the rock due to the earth and the contact force on the earth
due to the rock are action-reaction pairs.
c) The contact force on the earth due to the rock and the gravitational force on the earth
due to the rock are action-reaction pairs.
d) The gravitational force on the earth due to the rock and the contact force on the earth
due to the rock are action-reaction pairs.
e) None of the above
10) A certain spring has a length of 3.5 cm when no forces are applied. When 5.2 N is
applied the spring has a length of 7.0 cm. If the force on the spring is increased to 7.8 N,
then the length of the spring is, in cm
a) 4.49
b) 5.00
c) 5.25
d) 8.75
e) 9.25
11) An airplane is flying in horizontal flight at a constant velocity. The weight of the
airplane is 40,000 N. The wings produce a lift force that is perpendicular to the wings and
a drag force that is parallel to the wing. The engine produces a forward thrust force of
2,000 N. Which of the following statements is true?
a) The lift force on the airplane is zero.
b) The drag force on the airplane is zero.
c) The lift force on the airplane is 42,000 N upward.
d) The drag force on the airplane is 38,000 N backward.
e) The drag force on the airplane is 2,000 N backward.
12) In the figure above, a airport luggage carrying train with a tractor T is pulling three
luggage carts, M1 , M 2 , and M 3 .with an acceleration of 1.2 m/s 2 . If T = 300 kg, M1 =
200 kg, M 2 =100 kg, and M 3 =100 kg, then the force in the connection between cart
M 2 and cart M1 is,
a) 2350 N
b) 480 N
c) 240 N
d) 120 N
e) 0 N
13) Two masses are suspended by cord that passes over a pulley with negligible mass.
The cord also has negligible mass. One of the masses, m1 , has a mass of 6.0 kg and the
other mass, m 2 , has a mass of 4.0 kg. The tension of the cord attached to m1 is,
a) 47 N
b) 59 N
c) 39 N
d) 24 N
e) 15 N
14) An object starts with an initial velocity of 4.0 m/s and accelerates with an
acceleration of + 4.0 m/s 2 that lasts for 6.0 seconds. It then decelerates at  2.0 m/s 2
until its velocity is 4.0 m/s. The total distance covered is,
a) 96 m
b) 100 m
c) 188 m
d) 192 m
e) 288 m
F
m1
m2
15) Two blocks M1 and M2 are initially at rest. M1 sits on top of M2. M1=10 Kg and
M2=20 Kg. The coefficient of static friction between the floor and M2=0.4 and the
coefficient of kinetic friction between the floor and M2=0.2. The coefficient of static
friction between M2 and M1 is 0.7 and the coefficient of kinetic friction between M1 and
M2=0.6. A force of 70 Newtons is applied horizontally on block M1. What happens?
a)
b)
c)
d)
e)
Block M1 moves at a constant velocity, Block M2 stationary
Block M1 stationary, Block M2 moves at a constant velocity
Block M1 accelerates, Block M2 accelerates
Block M1 accelerates, Block M2 stationary
Block M1 stationary, Block M2 stationary
16) Two masses are connected by a cord that passes over a pulley as shown in the figure
above. The pulley has negligible mass. Mass 2 moves on a horizontal surface with
friction and mass 1 is suspended vertically. The cord has negligible mass. What are the
correct equations based on Newton’s Second law assuming the masses are accelerating?
T is the tension in the cord, N is the normal force and Ff is the force of friction.
a) T-M1g = M1a
b) M1g-T=M1a
c) T-M1g=M1a
d) T-M1g=0
e) M1g-T=M1a
N-M2g=0
N-M2g=M2a
N-M2g=0
N-M2g=0
N-M2g=0
T-Ff =M2a
T-Ff=M2a
T+Ff=M2a
T-Ff=M2a
T-Ff=M2a