QUESTION 1

Q1 If a Saturn V rocket with an Apollo spacecraft attached had a combined mass of 2.9 x 10⁵kg and reached a speed of 11200 m/s, how much kinetic energy would it have?

Choose one 1 point

2.9 x 10⁵J

3.2 x 10⁹J

1.8 x 10¹³J

3.6 x 10¹³J

QUESTION 2

Q2 On August 10, 1972, a large meteorite skipped across the atmosphere above the western United States and western Canada, much like a stone skipped across water. The accompanying fireball was so bright that it could be seen in the daytime sky and was brighter than the usual meteorite trail. The meteorite's mass was about 4 x 10⁶kg; its speed was about 15 km/s. Had it entered the atmosphere vertically, it would have hit Earth's surface with about the same speed.

Calculate the meteorite's loss of kinetic energy (in joules) that would have been associated with the vertical impact.

Choose one 1 point

4 x 10⁶J

6 x 10¹⁰J

5 x 10¹⁴J

1 x 10¹⁵kg

QUESTION 3

Q3 An RC car skids across a kitchen floor and across anxycoordinate system from the origin to a point withxycoordinates (3.0 m, 4.0 m). During this slide the force of friction on the car is constant. The friction force has magnitude of 2.0 N and is directed at a counterclockwise angle of 100 from the positive direction of thex-axis. How much work is done by the friction force on the RC car during the displacement?

Choose one 1 point

6.8J

14.0J

24.0J

4.2J

QUESTION 4

Q4 A floating ice block is pushed through a displacement

=15^12^

along a straight embankment by rushing water, which exerts a force

=210^150^

on the block. How much work does the force do on the block during the displacement?

Choose one 1 point

-4770J

4950J

1350J

5670000J

GROUP 5Q5 Helicopter lift

Group 2 questions

A helicopter lifts an astronaut of mass 72 kg 15 m vertically from

the ocean by means of a cable. The acceleration of the astronaut isg/10.

QUESTION 5.1

5a) How much work is done on the astronaut by the force from the helicopter?

Choose one 1 point

10584J

1058J

11642J

9800J

QUESTION 5.2

5b) How much work is done on the astronaut by the gravitational force on the astronaut?

Choose one 1 point

10584J

-10584J

1058J

-1058J

QUESTION 6

Q6 During spring semester at MIT, residents of the parallel buildings of the East Campus dorms battle one another with large catapults that are made with surgical hose mounted on a window frame. A balloon filled with dyed water is placed in a pouch attached to the hose, which is then stretched through the width of the room. Assume that the stretching of the hose obeys Hooke's law with a spring constant of 100 N/m. If the hose is stretched by 5.00 m and then released, how much work does the force from the hose do to the balloon in the pouch by the time the hose reaches its relaxed length? (Hint: there is an easier way to do this than the work equation.)

Choose one 1 point

500J

25000J

250J

1250J

QUESTION 7

Q7 In Figure a/b/c (below), we must apply a force of magnitude 80 N to hold the block stationary atx= -2.0 cm (Fig. c). From that position, we then slowly move the block so that our force does +4.0 J of work on the spring-block system; the block is then again stationary. What is the block's position? (Hint: There are two answers.)

Choose one 1 point

Box on a level surface with a spring attached horizontally and connected to a wall.

+/- 0.02m

+/-.06m

+/- 0.031m

+/-0.049m

QUESTION 8

Q8 The loaded cab of an elevator has a mass of 3000 kg and moves 210 m up the shaft in 23 seconds at constant speed. What is the average power of the force the cable exerts on the cab?

Choose one 1 point

1278W

29400W

268400W

6174000W

QUESTION 9

Q9 A 100-kg block is pulled at a constant speed of 5.0 m/s across a horizontal floor by an applied force of 122 N directed 37 above the horizontal. What is the average power of the force on the block?

Choose one 1 point

490W

610W

61000W

48700W

QUESTION 10

Q10 What is the spring constant of a spring that stores 25 J of elastic potential energy when compressed by 7.5 cm from its relaxed length?

Choose one 1 point

667N/m

0.28N/m

0.89N/m

8889N/m

GROUP 11Q11 Ice in a bowl part 1

Group 5 questions

In the figure at below, a .002kg ice flake is released from the edge of a hemispherical bowl whose radiusris 0.22 m. The flake-bowl contact is frictionless.

hemispherical bowl whose radius r is 0.22 m

QUESTION 11.1

11a) How much work is done on the flake by the gravitational force during the flake's descent to the bottom of the bowl?

Choose one 1 point

0.0043J

-0.0043J

.00044J

-.00044J

QUESTION 11.2

11b) What is the change in the potential energy of the flake-Earth system during that descent?

Choose one 1 point

0.0043J

-.0043J

0.0044J

-.00044J

QUESTION 11.3

11c) If that potential energy is taken to be zero at the bottom of the bowl, what is its value when the flake is released?

Choose one 1 point

0.0043J

-.0043J

0.00044J

-0.00044J

QUESTION 11.4

11.d) If, instead, the potential energy is taken to be zero at the release point, what is its value when the flake reaches the bottom of the bowl?

Choose one 1 point

0.0043J

-0.0043J

0.00044J

-0.0044J

QUESTION 11.5

11e) If the mass of the flake were doubled, would the magnitudes of the four answers above increase, decrease, or remain the same?

Choose one 1 point

increase

decrease

Stay the same

GROUP 12Q12 Ice in a bowl Part 2

Group 3 questions

Same setup as above.

A .002kg ice flake is released from the edge of a hemispherical bowl whose radiusris 0.22 m. The flake-bowl contact is frictionless.

QUESTION 12.1

12a) What is the speed of the flake when it reaches the bottom of the bottom of the bowl?

Choose one 1 point

4.3m/s

2.1m/s

3.5m/s

1.8m/s

QUESTION 12.2

12b) If we substituted a second flake with twice the mass, what would its speed be?

Choose one 1 point

4.2m/s

3.6m/s

8.2m/s

2.1m/s

QUESTION 12.3

12c) If, instead, we gave the flake an initial downward speed along the bowl, would the first answer increase, decrease, or remain the same?

Choose one 1 point

increase

decrease

stay the same

GROUP 13Q13 Ice on a hill

Group 4 questions

A large block of ice with a mass of 3 kg slides without friction across the ground at 10 m/s. The block comes to a hill and starts to slide up it.

QUESTION 13.1

13a) What is the kinetic energy of the block at the bottom of the hill?

Choose one 1 point

30J

15J

150J

300J

QUESTION 13.2

13b) What will be the potential energy of the block when it comes to a stop on the slope of the hill?

Choose one 1 point

15J

30J

150J

300J

QUESTION 13.3

13c) How high will the block be when it comes to a stop?

Choose one 1 point

150m

15.3m

50m

5.1m

QUESTION 13.4

13d) When the block starts to slide back down and gains a kinetic energy of 100J, how much potential energy will it have?

Choose one 1 point

0J

50J

100J

150J

GROUP 14Q14 Center of Mass

Group 3 questions

The figure below shows a three-particle system, with masses

m₁= 3.0 kg,m₂= 4.0 kg, andm₃= 8.0 kg. What is:

m1 at (0,0), m2 at (2,1), m3 at (1,2)

QUESTION 14.1

14a) Thex-coordinate of the system's center of mass?

Choose one 1 point

0

1.1

0.7

16.0

QUESTION 14.2

14b) They-coordinate of the system's center of mass?

Choose one 1 point

0

0.7

1.3

20

QUESTION 14.3

14c) Ifm₃is gradually increased, does the center of mass of the system shift toward or away from the particle, or does it remain stationary?

Choose one 1 point

toward

away

stationary

QUESTION 15

Q15 A particle of mass 2.00 kg has thexycoordinates (-1.20 m, 0.500 m). A particle of mass 4.00 kg has thexycoordinates (0.600 m, -0.750 m). Both lie on a horizontal plane. A particle of mass 3.00 kg is placed such that the center of mass of the three-particle system has the coordinates (-0.500 m, -0.700 m).

The added 3kg particle will need to be at position:=^+^

rx=A

Choose an answer

B

Choose an answer

ry=C

Choose an answer

D

Choose an answer

Choose an answer 1 point

GROUP 16Q16 Dropping stones

Group 2 questions

A stone is dropped att= 0. A second stone, with twice the mass of the first, is dropped from the same point att= 0.1s.

QUESTION 16.1

16a) How far below the release point is the center of mass of the two stones att= 0.3s? (Assuming neither stone has yet reached the ground.)

Choose one 1 point

0.44m

0.28m

.68m

0.21m

QUESTION 16.2

16b) How fast is the center of mass of the two-stone system moving at that time?

Choose one 1 point

0m/s

1.1m/s

2.3m/s

3.1m/s

QUESTION 17

Q17 Two skaters, one with mass 65 kg and the other with mass 40 kg, stand on an ice rink holding a pole of length 10 m and negligible mass. Starting from the ends of the pole, the skaters pull themselves along the pole until they meet. How far does the 40-kg skater move?

Choose one 1 point

650m

105m

3.8m

6.2m

10m

QUESTION 18

Q18 A ball of mass 0.70 kg is moving horizontally with a speed of 5.0 m/s when it strikes a vertical wall. The ball rebounds with a speed of 2.0 m/s. What is the magnitude of the change in linear momentum of the ball?

Choose one 1 point

3.0 kgm/s

7.0 kgm/s

4.9 kgm/s

2.1kgm/s

GROUP 19Q19 Impulse

Group 4 questions

A force in the negative direction of anx-axis is applied for 27 ms to a ball of mass 0.40 kg initially moving at 14 m/s in the positive direction of the axis. The force varies in magnitude, and the impulse has a magnitude of 32.4 Ns.

QUESTION 19.1

19a) What is the direction of the impulse on the ball?

Choose one 1 point

positive x-direction

negative x-direction

it is a scalar

QUESTION 19.2

19b) What is the ball's speed just after the force is applied?

Choose one 1 point

18.4m/s

14m/s

26.8m/s

67m/s

QUESTION 19.3

19c) What direction is the ball traveling in just after the force is applied?

Choose one 1 point

positive x-direction

negative x-direction

it is stationary

QUESTION 19.4

19d) What is the average magnitude of the applied force?

Choose one 1 point

32.4N

64.8N

1200N

1600N

QUESTION 20

Q20 A 100-kg man is standing next to a 5-kg box on a frictionless surface. He gives the box a kick, and it ends up having a velocity of 8 m/s to the right. What is the final velocity of the man after the kick?

Choose one 1 point

-0.4m/s

0.4m/s

-40m/s

40m/s

-1.3m/s

1.3m/s

GROUP 21Q21 Bullet block

Group 2 questions

A 0.0052-kg bullet moving at 672 m/s strikes a 0.700-kg wooden block at rest on a frictionless surface. The bullet emerges, traveling in the same direction, with its speed reduced to 428 m/s.

QUESTION 21.1

21a) What is the resulting speed of the block?

Choose one 1 point

244m/s

1.3m/s

1.81m/s

2.03m.s

QUESTION 21.2

21b) What is the speed of the bullet-block center of mass?

2.38m/s

3.53m/s

4.13m/s

4.96m/s