QUESTION 1.1

What is the weight of the water this boat displaces when floating in salt water of density 1.10 x 10³ kilograms per cubic meter?

0N

1,100N

35000N

36100N

QUESTION 1.2

What is the difference between the volume of fresh water displaced and the volume of salt water displaced?

Choose one ? 5 points

0m³

1000m³

0.1m³

0.32m³

GROUP 2Q2 Anchor

Group ? 2 questions

An iron anchor of density 7870 kilograms per cubic meter appears 200-netwons lighter in water than in air.

QUESTION 2.1

What is the volume of the anchor?

Choose one ? 5 points

200m³

7.8m³

0.02m³

1.8m³

QUESTION 2.2

How much does the anchor weigh in air?

7870N

157.4N

77126N

1500N

GROUP 3Q3 Strobe light on a disk

Group ? 4 questions

A disk that rotates clockwise at angular speed 10?radians per second is illuminated by only a flashing stroboscopic light. The flashes reveal a small black dot on the rim of the disk. In the initial flash, the dot appears at the 12:00 position (as on an analog clock face). Call the next five flashes f₁, f₂, and so on.

QUESTION 3.1

If the time between the flashes is 0.20 seconds, where does the dot appear at f₁?

Choose one ? 3 points

12:00 (up)

3:00(right)

6:00(down)

9:00(left)

QUESTION 3.2

If the time between the flashes is 0.20 seconds, where does the dot appear at f₂?

Choose one ? 2 points

12:00(up)

3:00(right)

6:00(down)

9:00(left)

QUESTION 3.3

If the time between flashes is 0.050 seconds instead, where does the dot appear at f₁?

Choose one ? 3 points

12:00(up)

3:00(right)

6:00(down)

9:00(left)

QUESTION 3.4

If the time between flashes is 0.050 seconds, where does the dot appear at f₂?

Choose one ? 2 points

12:00(up)

3:00(right)

6:00(down)

9:00(left)

GROUP 4Q4 Rotating a disk

Group ? 3 questions

Starting from rest, a disk rotates about its central axis with constant angular acceleration.

In 5.0 seconds, it rotates 25 radians. During this time:

QUESTION 4.1

What is the magnitude of the angular acceleration?

Choose one ? 4 points

2rad/s²

12.5rad/s²

20rad/s²

5rad/s²

QUESTION 4.2

What is the magnitude of the average angular velocity?

Choose one ? 3 points

25rad/s

20rad/s

5rad/s

2.5rad/s

QUESTION 4.3

What is the instantaneous angular velocity of the disk at the end of the 5.0 s?

Choose one ? 3 points

25rad/s

10rad/s

15rad/s

5rad/s

GROUP 5Q5 2 cylinders

Group ? 2 questions

Two uniform solid cylinders, each rotating about its central (longitudinal) axis, have the same mass of 1.25 kilograms and rotate with the same angular speed of 235 radians per second, but they differ in radius.

QUESTION 5.1

What is the rotational kinetic energy of the smaller cylinder, of radius 0.25 m?

Choose one ? 5 points

0.4J

9.2J

2157J

1080J

QUESTION 5.2

What is the rotational kinetic energy of the larger cylinder, of radius 0.75 m?

Choose one ? 5 points

0.35J

82.6J

19400J

9700J

GROUP 6Q6 Bicycle pedal

Group ? 3 questions

The length of a bicycle pedal arm is 0.152 meters, and a downward force of 111 newtons is applied to the pedal by the rider.

QUESTION 6.1

What is the magnitude of the torque about the pedal arm's pivot when the arm is at angle 30 with the vertical?

Choose one ? 4 points

8.4Nm

16.9Nm

14.6Nm

5.3Nm

QUESTION 6.2

What is the magnitude of the torque about the pedal arm's pivot when the arm is at angle 90 with the vertical?

Choose one ? 3 points

16.9Nm

0Nm

8.4Nm

24.1Nm

QUESTION 6.3

What is the magnitude of the torque about the pedal arm's pivot when the arm is at angle 180 with the vertical?

Choose one ? 3 points

0Nn

16.9Nm

18.7Nm

8.4Nm

QUESTION 7

Q7 A 140-kilogram hoop rolls along a horizontal floor so that the hoop's center of mass has a speed of 0.150 meters per second. How much work must be done on the hoop to stop it?

Choose one ? 10 points

-3.15J

-140J

-21J

-1.6J

GROUP 8Q8 Automobile engine

Group ? 2 questions

The angular speed of an automobile engine is increased at a constant rate from

120 radians per second to 300 radians per second in 12 seconds.

QUESTION 8.1

What is its angular acceleration in radians per seconds squared?

Choose one ? 5 points

180rad/s²

-180rad/s²

15rad/s²

87rad/s²

QUESTION 8.2

What is the total angle change of the wheel?

Choose one ? 5 points

180rads

1440rads

1620rads

2520rads

GROUP 9Q9 flywheel

Group ? 2 questions

A flywheel with a radius of 0.6 meters is rotating at an angular speed of

45 radians per second.

QUESTION 9.1

What is the linear speed of a point on the rim of the flywheel?

Choose one ? 5 points

27m/s

75m/s

45.6m/s

143m/s

QUESTION 9.2

What constant angular acceleration will increase the wheel's angular speed to 150 radians per second in 60.0 seconds?

Choose one ? 5 points

105rad/s²

1.75rad/s²

2.5rad/s²

0.75rad/s²

GROUP 10Q10 10-meter long bar

Group ? 3 questions

A 10-meter-long metal bar is anchored at one end so that it can rotate freely. Assume the pivot point is at the origin and the bar is on the reference line in cylindrical coordinates.

QUESTION 10.1

What would be the net torque on the bar ifa force [F 2 1D\"? + %9 } were applied to the 5meter point on the bar? What would be the net torque on the bar ifa force [F = 1H\"? + %} were applied to the Fmeter point on the bar? What would be the net torque on the bar if a force (F = 10r + ,0 )were applied to the 10-meter point on the bar?Q12 What must be the distance between point charge q1 = 2.60 at 10'5 coulomb and point charge :32 = 4.7I|] a: 105 coulomb forthe electrostatic force between them to have a magnitude of 5.?[1 newtons? QUESTION 13 Q13 What is the magnitude of a point charge whose electric field is 0.5 meters away, and has a magnitude of 2.0 newtons per coulomb? Choose one . 10 points O 1.250 O 1.12 * 10-10C O 5.6 * 10-1lc O 0.140\fsnoup14 Q14 Three Particles Group . 2 questions Two particles. A and B. are held in place on a table. Particle A is located at [2 meters, [1 meters} and has a charge of +5 coulombs. Particle B is located at {[1 meters, 4 meters} and has a charge of ? coulombs. A third particle. C. is then added to the table at [D meters. t} meters] and is free to move without friction. Particle C has a charge of 2.5 coulombs and a mass of 'I D kilograms. QUESTION 14.1 What is the force on Particle C, expressed in unitvector form? F = Ft + F3}? FX=F_}