### Spring 2002 Physics 101 Hour Exam 1(25 questions)

The grading button and a description of the scoring criteria are at the bottom of this page. Basic questions are marked by a single star *. More difficult questions are marked by two stars **. The most challenging questions are marked by three stars ***.

This exam consists of 25 questions; true-false questions are worth 2 points each, three-choice multiple choice questions are worth 3 points each, five-choice multiple choice questions are worth 6 points each. The maximum possible score is 114. When the exam was given, the mean was 89.3; the median was 93. Click here to see the formula sheet that came with the exam.

### QUESTION 1*

This and the following question concern the same physical situation.

An object starts from rest at t= 2 s at an initial position of x = 7.2 m and moves with constant acceleration.  At t = 6 s, the object is at x = -4.4 m.  What is the magnitude of the acceleration of the object?

(a)   5.80 m/s2
(b)   0
(c)   16.95 m/s2
(d)   1.45 m/s2
(e)   11.3 m/s2

### QUESTION 2*

What is the average velocity of the object?

(a)   11.60 m/s
(b)   2.90 m/s
(c)   22.6 m/s

### QUESTION 3**

A ball is thrown from the top of a building, which is 98 m high, with an initial downward velocity of 5 m/s.  How much time elapses before the ball hits the ground?

(a)   2.0 s
(b)   1.0 s
(c)   3.0 s
(d)   5.0 s
(e)   4.0 s

### QUESTION 4*

A batter hits a baseball straight upward at home plate and the ball is caught by the catcher 5.0 s after it is struck.  Assume the ball is hit and caught at the same location.  What is the speed of the ball when it is caught?

(a)   36.6 m/s
(b)   18.7 m/s
(c)   24.5 m/s
(d)   12.2 m/s
(e)   48.4 m/s

### QUESTION 5*

This and the following question concern the same physical situation.

A ball rolls off a horizontal surface of a 1.5 m high table with an initial horizontal speed of 2.0 m/s.  At what distance from the edge of the table will it land on the floor?

(a)   0.55 m
(b)   1.1 m
(c)   2.2 m
(d)   3.3 m
(e)   4.4 m

### QUESTION 6*

Let your answer to the preceding problem be D.  Now suppose the table is twice as high and that the initial horizontal speed is the same.  At what distance from the edge of the table will the ball land on the floor?

(a)   1.4 D
(b)   2 D
(c)   4 D

### QUESTION 7*

This and the following two questions concern the same physical situation.

A cannon ball is fired at an angle of 22° above horizontal with an initial speed v0 = 300 m/s, reaching a maximum height h before hitting the ground.

What is the maximum height h reached by the ball?

(a)   644 m
(b)   782 m
(c)   981 m
(d)   2420 m
(e)   3185 m

### QUESTION 8**

What is the speed of the ball when it reaches its maximum height?

(a)   300 m/s
(b)   0 m/s
(c)   278 m/s

### QUESTION 9*

Suppose the maximum height is h.  Suppose now the cannon is fired at the same angle but with twice the initial speed (600 m/s).  What will be the maximum height reached by the ball?

(a)   2 h
(b)   3 h
(c)   4 h

### QUESTION 10**

This and the following question concern the same physical situation.

The space shuttle is in a circular orbit around the earth at an altitude of about 6000 m from the center of the earth.  It makes one complete orbit in about 90 minutes.  What is the acceleration of the shuttle towards the center of the earth?

(a)   8.1 × 10-3m/s2
(b)   2.5 × 10-4m/s2
(c)   6.1 × 10-5m/s2
(d)   44 m/s2
(e)   0 m/s2

### QUESTION 11*

The moon is also in a circular orbit around the earth at a much greater distance than the space shuttle.  The acceleration of the moon towards the earth is

(a)   the same as that of the shuttle.
(b)   greater than that of the shuttle.
(c)   less than that of the shuttle.

### QUESTION 12*

This and the following question concern the same physical situation.

A pilot must fly her plane due north to reach her destination.  The plane flies at 300 km/h in still air.  If a wind is blowing from the west at 60 km/h, what is the direction the pilot must head her plane in order to fly straight north?

(a)   6.1° east of north
(b)   12.2° east of north
(c)   14.2° west of north
(d)   due west
(e)   11.5° west of north

### QUESTION 13***

Assuming she is heading in the direction found in the previous problem, the speed of the plane relative to the ground is

(a)   greater than 300 km/h.
(b)   300 km/h.
(c)   less than 300 km/h.

### QUESTION 14*

This and the following two questions concern the same physical situation.

A block of mass m1 = 2 kg is on a frictionless horizontal surface.  A light string that passes over frictionless and massless pulley pulls it.  The other end of the string is connected to a block of mass m2 = 3 kg.  What is the acceleration of the blocks?

(a)   2.94 m/s2
(b)   2.0 m/s2
(c)   11.7 6m/s2
(d)   4.0 m/s2
(e)   5.88 m/s2

### QUESTION 15**

What is the tension in the string?

(a)   greater than 29 N
(b)   less than 29 N
(c)   29 N

### QUESTION 16*

Let the tension in the preceding problem be T.  Suppose now that there is sliding friction between the 2 kg block and the horizontal surface.  The tension in the string will be

(a)   equal to T.
(b)   larger than T.
(c)   smaller than T.

### QUESTION 17*

This and the following question concern the same physical situation.

A small disk of mass m = 0.2 kg is tied to the end of a light string and twirled at constant speed v = 3 m/s in a circle of radius R = 4 m on a horizontal frictionless surface. What is the tension in the string?

(a)   0.45 N
(b)   0.6 N
(c)   1.8 N
(d)   2.7 N
(e)   0.23 N

### QUESTION 18*

Let F be the answer to the previous problem.  Suppose the radius of the circle is changed to 8 m.  The tension in the string is now

(a)   greater than F.
(b)   equal to F.
(c)   less than F.

### QUESTION 19*

A 50-kg crate rests on the bed of a truck which is accelerating to the right with a = 3.9 m/s2.  What is the minimum coefficient of static friction between the surface of the truck and the crate such that the crate does not slip?

(a)   0.1
(b)   0.2
(c)   0.3
(d)   0.4
(e)   0.5

### QUESTION 20*

This and the following question concern the same physical situation.

A skier glides down a frictionless slope that is inclined at q = 13° to the horizontal. What is the acceleration of the skier?

(a)   0.58 m/s2
(b)   2.2 m/s2
(c)   9.81 m/s2
(d)   0.15 m/s2
(e)   0.29 m/s2

### QUESTION 21**

Suppose instead that the coefficient of kinetic friction between the skis and the snow is 0.20.  What is the acceleration of the skier?

(a)   0.58 m/s2
(b)   2.2 m/s2
(c)   9.81 m/s2
(d)   0.15 m/s2
(e)   0.29 m/s2

### QUESTION 22*

A box with an initial speed of 15 m/s slides along a surface where the coefficient of sliding friction is 0.45.  How long does it take for the block to come to rest?

(a)   1.5 s
(b)   3.4 s
(c)   6.8 s
(d)   8.5 s
(e)   4.7 s

### QUESTION 23**

A box of mass M rests on the floor of an elevator which is going up the Sears tower.  As it approaches the top, the elevator starts to slow down.  At this point, the normal force exerted by the floor on the box is

(a)   less than Mg.
(b)   equal to Mg.
(c)   greater than Mg.

### QUESTION 24**

This and the following question concern the same physical situation.

In the diagram, two adjacent blocks of mass 2 kg and 4 kg are free to slide on a horizontal frictionless surface.  A force F=6 N is applied to the 2 kg block.

The net force on the 2 kg block is

(a)   greater than 6 N.
(b)   equal to 6 N.
(c)   less than 6 N.

### QUESTION 25**

The net force on the 4 kg block is

(a)   greater than the net force on the 2 kg block.
(b)   equal to the net force on the 2 kg block.
(c)   less than the net force on the 2 kg block.

Scoring of True-False (T,F) Questions:
• If you mark the correct answer, you get 2 points.
• If you mark the wrong answer or if you mark neither answer, you get 0 points.
Scoring of Multiple Choice I (a,b,c) Questions:
• If you mark the correct answer, you get 3 points.
• If you mark a wrong answer or if you mark none of the answers, you get 0 points.
Scoring of Multiple Choice II (a,b,c,d,e) Questions:
• If you mark one answer and it is the correct answer, you get 6 points.
• If you mark two answers and one of them is the correct answer, you get 3 points.
• If you mark three answers and one of them is the correct answer, you get 2 points.
• If you do not mark the correct answer, or if you mark more than three answers, or if you mark none of the answers, you get 0 points.