Download 07/18/08 Name, Roster # Physics 151 Midterm 1 The following

07/18/08
Name, Roster #
Physics 151 Midterm 1
The following graphs show an objects position as a function of time. The object moves in one dimension, where the positive
x direction is to the north and the negative x direction is to the south. For these questions, more than one choice may apply
1. Which of the above graphs represents an object that is slowing down?
A
B
C
D
E
F
G
2. Which of the above graphs represents an object that is moving to the south at a constant speed?
A
B
C
D
E
F
G
3. Which of the above graphs represents an object that is not moving?
A
B
C
D
E
F
G
4. Which of the above graphs above represent an object with a net force to the south acting on it?
A
B
C
D
E
F
G
5. Which of the above graphs represents an object moving to the north and accelerating to the north?
A
B
C
D
E
F
G
07/18/08
Name, Roster #
Physics 151 Midterm 1
The following information pertains to questions 6-9: Three roaches
are playing with a toy truck on a moving sidewalk like those found
at the airport. Huey is sitting on the ground next to the moving sidewalk.
Louie is sitting on the moving sidewalk. The moving sidewalk moves
2.0 m/s due south relative to the ground. Dewey is running with a velocity
of 3.0 m/s due east relative to the toy truck. The toy truck is moving with
a velocity of 4.0 m/s due south relative to the moving sidewalk.
6. What is the speed of the toy truck relative to Louie?
a. 2.0 m/s
b. 3.6 m/s
d. 5.0 m/s
e. 6.0 m/s
g. None of the above
c. 4.0 m/s
f. 6.7 m/s
7. What is the speed of the toy truck relative to Huey?
a. 2.0 m/s
b. 3.6 m/s
d. 5.0 m/s
e. 6.0 m/s
g. None of the above
c. 4.0 m/s
f. 6.7 m/s
8. What is the speed of Dewey relative to Louie?
a. 2.0 m/s
b. 3.6 m/s
d. 5.0 m/s
e. 6.0 m/s
g. None of the above
c. 4.0 m/s
f. 6.7 m/s
9. What is the direction of Dewey's velocity relative to Huey?
a. 34º south of due east
c. 63º south of due east
e. None of the above
b. 34º east of due south
d. 63º east of due south
10. A ball is dropped into a river from a very high bridge. At, the same time, another ball is thrown down towards the
water. If air resistance is negligible, the acceleration of the balls just before they strike the water
a.
b.
c.
d.
is greater for the dropped ball.
is greater for the thrown ball
is the same for both balls
depends on the height of the bridge
07/18/08
Name, Roster #
Physics 151 Midterm 1
The following information pertains to questions 11 and 12:
A race car is traveling on a horizontal track as shown to the right.
At point A, the car is slowing down and at point B, the car is speeding
up.
11. On the diagram to the right, draw in the vectors that represent
the car's radial, tangential and total accelerations at point A.
(i.e. at point A draw in arrow representing
ar , at , a )
12. On the diagram to the right, draw in the vecors that represent
the car's radial, tangential and total accelerations at point B.
(i.e. at point B draw in arrow representing
ar , at , a )
13. Recall that the winner of the 100 m dash in the Olympics takes about 10 seconds
to finish the race. Suppose a person could run at this rate indefinitely ( this is not
physically possible) approximately how long would it take this person to run a
mile?
a. 1 minute
b. 3 minutes
c. 5 minutes
d. 10 minutes
The following information pertains to questions 14 and 15:
Suppose a motorcycle starts at rest anc accelerates uniformly. At time t
the motorcycle has a speed of 40 m/s and has covered a distance of 80 m.
14. What is the motorcycle's speed at time t/2?
a. 10 m/s
b. 20 m/s
c. 80 m/s
d. 160 m/s
e. Impossible to tell since we don't know a (the acceleration)
15. What distance has the motorcycle covered at time t/2?
a. 20 m
b. 40 m
c. 160 m
d. 320 m
e. Impossible to tell since we don't know a (the acceleration)
07/18/08
Name, Roster #
Physics 151 Midterm 1
The following information pertains to questions 16 and 17:
A block of mass 10.0 kg has two ropes attached to it as shown.
The tension in the left rope is 8.0 N and the tension in the
right rope is 4.0 N. Initially the block is moving to the right
with a speed of 1.2 m/s. Assume there is no friction between the
block and the surface below, the effects of air resistance are negligible, and the tension in the ropes remains constant.
16. How fast is the block moving 2.0 s later?
a. 0.2 m/s
f. 1.2 m/s
b. 0.4 m/s
g. 1.4 m/s
c. 0.6 m/s
h. 1.6 m/s
d. 0.8 m/s
i. 1.8 m/s
e. 1.0 m/s
j. 2.0 m/s
17. What is the furthest distance to the right the block reaches with respect to its initial position?
a. 0.9 m
b. 1.8 m
e. None of the above
c. 3.6 m
d. 7.2 m
The following information pertains to questions 18-20:
A soccer ball is kicked from the ground with an initial velocity of 24 m/s at an angle of 30º above the horizontal.
Assume that air resistance is negligible and the acceleration of gravity is 10.0 m/s2 down.
18. How long is the ball in the air?
a. 1.2 s
b. 1.4 s
e. None of the above
c. 2.4 s
d. 2.8 s
c. 14 m
d. 20 m
19. How high does the ball go?
a. 7.2 m
b. 9.8 m
g. None of the above
e. 29 m
f. 39 m
e. 24 m/s
f. 28 m/s
20. What is the speed of the ball at the highest point in its path?
a. 0
b. 12 m/s
g. None of the above
c. 14 m/s
d. 21 m/s
07/18/08
Name, Roster #
Physics 151 Midterm 1, Problem 1
A boulder is rolling horizontally with a velocity of 20 m/s to the right. The boulder rolls off the cliff horizontally and lands
in the lake.
a. How long after it rolls of the cliff does it land in the lake? [8 points]
b. How far from the edge of the cliff will it land in the lake?[ 6 points]
c. How fast will it be going when it hits the water in the lake?[6 pts]
07/18/08
Name, Roster #
Physics 151 Midterm 1, Problem 2
Shown above is the Boeing-747, this huge plane can seat over 400 passengers. The mass of the fully loaded plane is
3.80 x 105 kg and its four engines can provide a maximum thrust (force in the forward direction) of 9.60 x 105 N.
a. Let's assume we are sitting on the runway getting ready to takeoff. Assuming we can neglect friction and air resistance,
what is the maximum forward acceleration the 747 can achieve? [ 5 points]
b. To safely take-off the 747 must reach a speed of approximately 80 m/s. Assuming the 747 accelerates uniformly at its
maximum value, what is the minimum length a runway must be to allow the 747 to reach its take off speed. In reality, the
minimum take-off distance is about 2.5 times this length. [10 points]
c. The 747 has a cruising speed of 550 mph at an altitude of 35,000 feet. Suppose a 747 is moving in a straight line at its
cruising speed, what is the net force acting on the 747 at this time? [5 points]