A fan rotating with an initial angular velocity of 1000 rev/min is switched off. In 2 seconds, the angular

velocity decreases to 200 rev/min. Assuming the angular acceleration is constant, how many revolutions

does the blade undergo during this time?

1. 10

2. 20

3. 100

4. 125

5. 1200

Question 2

A rigid body rotates about a fixed axis with a constant angular acceleration. Which one of the following

statements is true concerning the tangential acceleration of any point on the body?

1. Its magnitude is zero m/s2.

2. It depends on the angular velocity.

3. It is equal to the centripetal acceleration.

4. It is constant in both magnitude and direction.

5. It depends on the change in the angular velocity.

Question 3

A solid disk rolls without slipping on a horizontal surface so that its center proceeds to the right with

a constant speed. Which one of the following statements concerning the direction of the disk’s angular

velocity is true?

1. It points to the left.

2. It points to the right.

3. It points into the paper.

4. It points out of the paper.

5. It varies from point to point on the disk.

28 PHY1015/101/3/2010

Question 4

A bicycle with wheels of radius 0.4 m travels on a level road at a speed of 8 m/s. What is the angular of

the wheels?

1. 10 rad/s

2. 20 rad/s

3.

10 rad/s

4. 10 rad/s

5. 20

rad/s

Question 5

Complete the following statement: A body is in translational equilibrium

1. only if it is at rest.

2. only if it is moving with constant velocity.

3. only if it is moving with constant acceleration.

4. if it is either at rest or moving with constant velocity.

5. if it moving with either constant velocity or constant acceleration.

Question 6

Complete the following statement: When a net torque is applied to a rigid object it always produces a

1. constant acceleration.

2. rotational equilibrium.

3. constant angular velocity.

4. constant angular momentum.

5. change in angular velocity.

29 PHY1015/101/3/2010

Question 7

A horizontal 10 m plank weighs 100 N. It rests on two supports that are placed 1.0 m from each end as

shown in the figure below. How close to one end can an 800 N person stand without causing the plank to

tip?

1. 0 m

2. 0.2 m

3. 0.5 m

4. 0.6 m

5. 0.8 m

Question 8

An 80 kg man balances the boy on a teeter-totter as shown in the figure below. Ignoring the weight of

the board, what is the approximate mass of the boy?

1. 10 kg

2. 20 kg

3. 40 kg

4. 45 kg

5. 50 kg

30 PHY1015/101/3/2010

Question 9

Consider the four point masses located as shown in the figure below. The acceleration due to gravity is

the same everywhere. What is the x coordinate of the center of gravity for this system.

1. 2.0 m

2. 2.7 m

3. 3.0 m

4. 3.3 m

5. 3.8 m

Question 10

Which one of the following statements most accurately describes the center of gravity of an object?

1. It is the point where gravity acts on the object.

2. It is the point where all the mass is concentrated.

3. It must be experimentally determined for all objects.

4. It is the point on the object where all the weight is concentrated.

5. It is the point from which the torque produced by the weight of the object can be calculated.

31 PHY1015/101/3/2010

Question 11

The drawing shows the top view of a door that is 2 m wide. Two forces are applied to the door as

indicated. What is the magnitude of the net torque on the door with respect to the hinge?

1. 0 N ·m

2. 5.0 ·m

3. 8.7 ·m

4. 10.0 ·m

5. 26.0 ·m

Question 12

Three objects are attached to a massless rigid rod that has an axis of rotation as shown in the figure below.

Assuming all of the mass of each object is located at the point shown for each, calculate the moment of

inertia of this system.

1. 1.3 kg·m2

2. 3.1 kg·m2

3. 5.3 kg·m2

4. 7.2 kg·m2

5. 9.1 kg·m2

32 PHY1015/101/3/2010

Question 13

A 50 kg rider on a moped of mass 75 kg is traveling with a speed of 20 m/s. The two wheels of the moped

have a radius of 0.2 m and a moment of inertia of 0.2 kg·m2. What is the rotational kinetic energy of the

wheels?

1. 80 J

2. 100 J

3. 500 J

4. 2000 J

5. 4000 J

Question 14

A spinning star begins to collapse under its own gravitational pull. Which one of the following occurs as

the star becomes smaller?

1. Its angular velocity decreases.

2. Its angular momentum increases.

3. Its angular velocity remains constant.

4. Its angular momentum remains constant.

5. Both its angular momentum and its angular velocity remain constant.

Question 15

A solid sphere of radius R rotates about a diameter with an angular speed !. The sphere then collapses

under the action of internal forces to a final radius R/s. What is the final angular speed of the sphere?

1. !/4

2. !/2

3. !

4. 2!

5. 4!

Question 16

A 1.0 kg object is suspended from a spring with k = 16 N/m. The mass is pulled 0.25 m downward from

its equilibrium position and allowed to oscillate. What is the maximum kinetic energy of the object?

1. 0.25 J

2. 0.50 J

3. 1.0 J

4. 2.0 J

5. 4.0 J

33 PHY1015/101/3/2010

Question 17

The pendulum is transported from sea-level, where the acceleration due to gravity g = 9.80 m/s2, to the

bottom of a valley. At this location, the period of the pendulum is decreased by 3.00%. What is the value

of g in the valley?

1. 9.22 m/s2

2. 9.51 m/s2

3. 9.80 m/s2

4. 10.1 m/s2

5. 10.4 m/s2

Question 18

What is the period of a pendulum consisting of a 6 kg object oscillating on a 4 m string?

1. 0.25 s

2. 0.50 s

3. 1.0 s

4. 2.0 s

5. 4.0 s

Question 19

A simple pendulum consists of a ball of mass m suspended from the ceiling using a string of length L.

The ball is displaced from its equilibrium position by an angle . What is the magnitude of the restoring

force that moves the ball toward its equilibrium position and produces a simple harmonic motion?

1. kx

2. mg

3. mg(cos )

4. mg(sin )

5. mgL(sin )

Question 20

A cable stretches by an amount d when it supports a crate of mass M. The cable then cut in half. If the

same crate is supported by either half of the cable, by how much will the cable stretch?

1. d

2. d/2

3. d/4

4. 2d

5. 4d

34 PHY1015/101/3/2010

Question 21

The maximum compressional stress that a bone can withstand is 1.7×108 N/m2 before it breaks. A

thighbone (femur), which is the largest and longest bone in the human body, has a cross sectional area of

7.7×10−4 m2. What is the maximum compressional force that can be applied to the thighbone?

1. 2.1×1011 N

2. 1.2×105 N

3. 4.8×1012 N

4. 3.0×103 N

5. This cannot be determined since Young’s modulus is not given.

Question 22

Which one of the following statements concerning the buoyant force on an object submerged in a liquid

is true?

1. The buoyant force depends on the mass of the object.

2. The buoyant force depends on the weight of the object.

3. The buoyant force is independent of the density of the liquid.

4. The buoyant force depends on the volume of the liquid.

5. The buoyant force will increase with the depth if the liquid is incompressible.

Question 23

Complete the following statement: Bernoulli’s principle is a statement of

1. hydrostatic equilibrium.

2. thermal equilibrium in fluids.

3. mechanical equilibrium in fluids.

4. energy conservation in dynamic fluids.

5. momentum conservation in dynamic fluids.

35 PHY1015/101/3/2010

Question 24

A large tank is filled with water to a depth of 15 m. A spout located 10.0 m above the bottom of the tank

is then opened as shown in the figure below. With what speed will water emerge from the spout?

1. 3.1 m/s

2. 9.9 m/s

3. 14 m/s

4. 17 m/s

5. 31 m/s

Question 25

A truck accelerates from rest at point A with constant acceleration of magnitude a and subsequently

passes points B and C as shown in the figure below. The distance between B and C is x, and the time

required for the truck to travel from B to C is t. Which expression determines the average speed of the

truck between the points B and C?

1. v2 = 2ax

2. v = x

t

3. v = xt

4. v = 1

2at2

5. v = at

36 PHY1015/101/3/2010

Question 26

A bullet is aimed at a target on the wall a distance L away from the firing position. Because of gravity,

the bullet strikes the wall a distance y below the mark as suggested in the figure below. If the distance

L were half as large, and the bullet had the same initial velocity, how would y be affected?

1. It will double.

2. It will be half as large.

3. It will be four times larger.

4. It will be one fourth large.

5. It is not possible to determine unless numerical values are given for distances.

Question 27

Consider the situations depicted by Case 1, Case 2 and Case 3 in the figure below. In which case will

the magnitude of the normal force on the block be equal to (Mg + F sin )?

1. case 1 only.

2. case 2 only.

3. Both cases 1 and 2.

4. Both cases 2 and 3.

5. cases 1, 2, and 3.

37 PHY1015/101/3/2010

Question 28

A 10 kg block is connected to a 40 kg block as shown in the figure below. The surface on which the blocks

slide is frictionless. A force of 50 N pulls the blocks to the right. What is the magnitude of the tension T

in the rope that connects the two blocks?

1. o N

2. 10 N

3. 20 N

4. 40 N

5. 50 N

Question 29

Consider a satellite in a circular orbit around the Earth. If it were at an altitude equal to twice the radius

of the earth, 2RE, how would its speed v be related to the Earth’s radius RE, and the magnitude g of the

acceleration due to gravity on the Earth’s surface?

1. v2 =

gRE

9

2. v2 = 2gRE

3. v2 =

gRE

3

4. v2 =

gRE

4

5. v2 =

gRE

2

38 PHY1015/101/3/2010

Question 30

A small car of mass M travels along a straight horizontal track. As suggested in the figure below, the

track then bends into a vertical circle of radius R. Which expression determines the minimum speed that

the car must have at the top of the track if it is to remain in contact with the track?

1. v = MgR

2. v = 2gR

3. v = p2gR

4. v = pgr

5. v = gR

Question 31

A 9.0 kg box of oranges slides from rest down a frictionless incline from a height of 5.0 m, as shown in the

diagram below. A constant frictional force, introduced at point A, brings the block to rest at point B,

19 m to the right of point A. What is the coefficient of kinetic friction, μk, of the surface from A to B?

1. 0.11

2. 0.26

3. 0.33

4. 0.47

5. 0.52

39 PHY1015/101/3/2010

Question 32

A ball of mass m is struck by a bat so that it acquires a speed v. If t represents the duration of collision

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