Name: ________________________ Class: ___________________ Date: __________
Exam 2--PHYS 201--Fall 2014
Multiple Choice
Identify the choice that best completes the statement or answers the question.
4. Given that A + B = C, and that |A|2 + |B|2 =|C|2, how
are vectors A and B oriented with respect to each
other?
a. perpendicular
b. separated by some unknown angle
c. parallel and in same direction
d. antiparallel (parallel but in opposite directions)
e. separated by 30 degrees
1. Consider these vectors. What is A-B?
a.
b.
c.
d.
5. A cart is being pulled along a horizontal track by
an external force and accelerating. A cannon on
the cart fires straight upwards. After it is fired,
what happens to the ball?
a
b
c
d
a.
b.
c.
2. Which of these are vector quantities?
I. mass
II. distance
III. velocity
IV. acceleration
a. I & III
b. III & IV
c. II, III, & IV
d. I
e. all of these
d.
the cannonball falls into the cart
the cannonball falls in front of the cart
it depends on the initial velocity of the
cannonball
the cannonball falls behind the cart
6. Which of these projectiles remains in the air for the
longest amount of time?
3. Which of these plots represents the y-component of
the velocity for an object launched from the ground
at an angle and returns to the same y-position?
a.
b.
c.
d.
a.
b.
c.
d.
e.
a
b
c
d
none of these
1
a
b
c
it depends on their initial velocity
10. A cart is on a horizontal frictionless table. Once
the cart has been pushed and released, what will
happen to it?
a. it will immediately come to a stop
b. it will continue at constant acceleration
c. it will gradually slow down
d. it will continue at constant velocity
7. You run out of gas. You and your friends have to
push your car out of the road. Which of these
statements best explain why it is difficult to move
the car?
a. the car has a big weight
b. the car experiences a very large frictional force
c. the car has a lot of mass
d. you and your friends are very weak
11. The normal force on an object is always:
a. equal to the gravitational force
b. abnormally large
c. perpendicular to the surface on which the
object sits
d. opposite the direction of the object’s motion
e. in the upward direction
8. A karate chop delivers a force of 3000 N to a board
that breaks. The force that the board exerts on the
hand during this event is
a.
b.
c.
d.
less than 3000 N
3000 N
greater than 3000 N
need more information
12. Which of these statements about the coefficients of
friction is true?
9. You push on a mass with a certain force, and the
mass accelerates at 1 m/s 2. With the same force,
you push on a second mass. The acceleration of
the second mass is 3 m/s2. Now, you stick the 2
masses together and push on them with the same
force. What is the acceleration of the 2 masses?
a.
b.
c.
d.
a.
b.
c.
µs > µk
µs < µk
µs = µk
13. You apply a force in the x-direction of 20 N on a
block that has a mass of 10 kg. If no other forces
act on the block, what is its acceleration?
a. 0.5m/s2
b. 200 m/s2
c. 5 m/s2
d. 2 m/s2
3 m
4
s2
3 m
2
s2
1 m
2
s2
2m 2
s
2
Problem
14. (10 pts) Vectors A and B add to give a resultant vector that has a magnitude of 5.83 m at 31 degrees above the
x-axis. The magnitude of vector A is 2.17 m along the +x axis. What are the magnitude and direction of vector
B?
3
15. (20 pts) A stone is thrown outward from the top of a 20-m high cliff with an upward velocity component (that is,
the y-component of the velocity) of 10 m/s.
a) How long is stone in the air?
b) If the ball lands 100 meters from the base of the cliff, what is the angle of the ball’s initial velocity?
c) What is the magnitude of the ball’s velocity when it reaches the ground?
Quadratic formula:
cos θ
1
=
sin θ tan θ
If, at 2 +bt+c=0,
−b ±
b 2 − 4ac
2a
4
16. (25 pts) A block (m1=20 kg) sits on an inclined plane (angle=30°); a rope connects the block to a second block
(m2=10 kg) that sits on a surface just above the inclined plane. Both blocks on the surfaces have a coefficient of
kinetic friction equal to 0.1.
a) What is the frictional force on the block m 1?
b) What is the frictional force on the block m 2?
c) What is the acceleration of the block m 1?
5
17. (15 pts) A block of mass 10 kg sits at rest on a horizontal surface. A force of 20 N is applied at 30 degrees from
the x-axis. The coefficient of kinetic friction between the block and surface is 0.1. (Hint: The normal force is not
equal to the weight.)
a) What is the normal force acting on the block?
b) At what rate does the block accelerate to the right?
6
ID: A
Exam 2--PHYS 201--Fall 2014
Answer Section
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
A
B
E
A
D
A
C
B
A
D
C
A
D
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
1
1
1
1
1
1
1
1
1
1
1
1
1
PROBLEM
14. ANS:
.
PTS: 1
15. ANS:
3.2s
PTS: 1
16. ANS:
.
PTS: 1
17. ANS:
90 N
0.8 m/s2
PTS: 1
1