ame: ________________________ Class: ___________________ Date: __________
ID: A
Exam 1--PHYS 101--Fall 2009
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. The standard unit of measure for the SI unit of time is based on which of these:
a.
____
characteristic frequency of the
c. a fraction of the sidereal day
cesium-133 atom
b. the time required for light to travel 1
d. average solar day
meter
2. Complete this arithmetic operation, keeping proper significant figures:
2.01 + 3.0 + 20.10 + 300.42
____
a. 325.53
d. 330
b. 325.5
e. 300
c. 326
3. You throw a ball towards the ground, it bounces, and returns to your hand. Which of these plots best
describes the motion of the ball from the moment you release it to the moment you catch it?
a.
c.
b.
d.
1
ame: ________________________
____
ID: A
4.
Which of these statements represent the motion represented in this plot?
____
a. increasing, negative velocity
c.
b. decreasing, negative velocity
d.
5. Which of these quantities is a scalar quantity?
increasing, positive velocity
decreasing, positive velocity
I. Mass
II. Speed
III. Time
IV. Distance
a.
b.
c.
II
II & IV
IV
d.
e.
2
I & III
All of these
ame: ________________________
____
____
ID: A
6. The following figure shows vectors ä
A and ä
B . What is the result of the sum ä
A +ä
B?
a.
c.
b.
d.
| | ä| | ä|
ä and | ä
ä
ä
7. If the vectors ä
A +ä
B=C
| A | + | B | = | C | . How are the vectors A and B related to one another?
a.
b.
they’re pointing in the same direction
they’re perpendicular to one another
c.
d.
3
they’re second cousins
they are pointing opposite one another
ame: ________________________
____
8. This figure shows the trajectories of 3 punts, each of which has the same initial velocity. What is the
relationship between the angles of launch, as measured from the +x axis, for each of the trajectories?
a.
b.
____
ID: A
θB < θ A < θC
θ A < θB < θC
c.
d.
θ A < θB = θC
θC < θB < θ A
9. You drop a package from a plane flying at a constant speed. Without air resistance, the package will:
a.
quickly lag behind the plane while falling c.
remain vertically under the plane while
falling
b. move ahead of the plane while falling
d. not enough information
____ 10. From rest, we step on the gas of our Ferrari, providing a force F for 10 secs, speeding it up to a final speed v.
If the applied force were twice the original force (2F), how long would it have to be applied to reach the same
final speed?
a.
b.
20 seconds
10 seconds
c.
d.
4
2 seconds
5 seconds
ame: ________________________
ID: A
____ 11. A mass sits on the bottom of an elevator that is in freefall with a downward acceleration of 9.8 m/s 2. Which
of these statements about the normal force acting on the block is true?
a. N=0
c. N>0
b. N=mg
d. N<0
____ 12. Antilock breaks keep the car wheels from locking up when you stop your car. Why does this help slow the
car down?
a.
b.
µk > µs so sliding friction is better
µs > µk so static friction is better
c.
d.
µk > µs so static friction is better
µs > µk so sliding friction is better
____ 13. In this graph, what is the instantaneous acceleration at point C?
a.
b.
c.
2 m/s2
-1 m/s2
1 m/s2
d.
e.
5
-2 m/s2
none of these
ame: ________________________
ID: A
____ 14. In square centimeters (cm2), what is the area of this paper?
a.
b.
600 cm2
60 cm2
c.
d.
6
60,000 cm2
6000 cm2
ame: ________________________
ID: A
Problem
15. (20 pts) The position of an object as a function of time is given r=(2.5-0.9t 2)i+(3.2t-0.4t2)j
m, where t is the time in seconds. What are the magnitude and direction of the
acceleration?
What is its velocity, in vector notation, after a time of 3.2 seconds?
7
ame: ________________________
ID: A
16. (15 pts) An arrow, fired with an initial velocity of 32 m/s at an angle of 30° above the
horizontal, travels 23 m horizontally before it hits the ground. What height was its maximum
height?
-
8
ame: ________________________
ID: A
17. (15 pts) A mass of 10 kg is attached to a spring with spring constant of 1200 N/m in an
elevator as shown in this figure. If the elevator is accelerating upwards at a rate of 3 m/s 2,
how much does the spring stretch from its equilibrium position (when there are no forces
acting on it)?
9
ame: ________________________
ID: A
-
10
ame: ________________________
ID: A
18. (20 pts) This figure shows two masses: m 1=2.1 kg and m 2=0.5 kg. The coefficient of kinetic
friction between block 2 and the plane is 0.4 ( µ=0.4). The angle of the plane is θ=30°.
a) What is the normal force acting on block #2?
b) What is the frictional force acting on block #2?
c) What is the acceleration of block #2?
11
ID: A
Exam 1--PHYS 101--Fall 2009
Answer Section
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
A
B
C
A
E
C
A
D
C
D
A
B
D
A
PTS:
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
1
PROBLEM
15. ANS:
PTS: 1
16. ANS:
PTS: 1
17. ANS:
PTS: 1
18. ANS:
PTS: 1
1