12 Questions

Practice quiz for chapter 7.

Questions and Answers

- 1.A solar collector heats the water in the water tank of a home. Which energy transformation equation best describes this situation?
- A.
Radiant --> thermal

- B.
Radiant --> electrical

- C.
Radiant --> gravitational --> electrical

- D.
Radiant --> gravitational --> thermal

- E.
Radiant --> thermal --> electrical

- 2.The amount of work done when a 80.00-kg person jumps 1.000 m into the air in 0.5000 s is
- A.
292.0 J

- B.
40.00 J

- C.
784.00 J

- D.
1568 J

- E.
160.0 J

- 3.The amount of work done to stop a bullet travelling through a tree trunk a distance of 50 cm with a force of 2.00 ´ 10
^{2}N is- A.
–4.00 x 102 J

- B.
+4.00 x 102 J

- C.
+1.00 x 102 J

- D.
–1.00 x 102 J

- E.
+1.00 x 104 J

- 4.A person lifts a pail of water of mass of 1.50 kg from the ground to a deck, 1.00 m above the ground. How much work was done by gravitational force on the pail of water?
- A.
–14.7 J

- B.
+1.50 J

- C.
–1.50 J

- D.
+0.153 J

- E.
+14.7 J

- 5.In which case is negative work done?
- A.
The work done by Earth on a ball as the ball, which was initially at rest, falls 3.0 m down towards Earth.

- B.
A eastward force is applied to an eastward moving soccer ball that is already moving at a constant velocity to increase its speed in that direction.

- C.
A cart is moving at a constant velocity of 10 m/s [W] when a 0.5 N [downward] force is applied.

- D.
The work done by Earth on an arrow as it is fired 200 m straight up into the air.

- E.
Earth applies a force on the Moon as the Moon travels one completion rotation in orbit around Earth.

- 6.In which case is positive work done?
- A.
The work done by air resistance on a ball as the ball, which was initially at rest, falls 3.0 m down towards Earth.

- B.
A eastward force is applied to an eastward moving soccer ball that is already moving at a constant velocity to increase its speed in that direction.

- C.
Earth applies a force on the Moon as the Moon travels one completion rotation in orbit around Earth.

- D.
A cart is moving at a constant velocity of 10 m/s [W] when a 0.5 N [downward] force is applied.

- E.
The work done by Earth on an arrow as it is fired 200 m straight up into the air.

- 7.An elevator motor lifts a load of 2500 kg a height of 12.0 m in 3.00 seconds. The energy required by the motor to accomplish this task is 300 000 J. What is the efficiency of the elevator?
- A.
10.0%

- B.
98.0%

- C.
30.0%

- D.
102%

- E.
8.17%

- 8.In the following figure, a 0.60-kg ball is about to fall to the step below. The gravitational potential energy of the ball relative to the step is
- A.
8.8 x 101 J

- B.
2.9 x 101 J

- C.
6.0 x 100 J

- D.
3.0 x 100 J

- E.
5.9 x 101 J

- 9.Jughead (m = 60 kg), Archie (m = 65 kg), and Reggie (m = 70 kg), all decide to run up a flight of stairs at with a height of 4.0 m at constant speed at good ol’ Riverdale High. If all three achieve this task in a time of 3.5 seconds, who generates the most power?
- A.
Jughead

- B.
Archie

- C.
Reggie

- D.
They all generate the same amount of power

- E.
Not enough information is provided to answer this question

- 10.During a recent NBA basketball game, Jose Calderon, a guard with the Toronto Raptors, threw a basketball into the crowd in an unsportsmanlike manner. Which one of the following statements about the basketball is FALSE?
- A.
As the basketball rises, its kinetic energy decreases

- B.
As the basketball rises, it is accelerated downward

- C.
As the basketball rises, its potential energy increases

- D.
When the basketball reaches the top of its flight, its kinetic energy is zero

- E.
When the basketball reaches the top of its flight, acceleration is still g

- 11.Nicholas exerts a certain force to lift a dumbell 3.0 m straight above his head in 20 s. If he had completed the same task in 10 s, the energy he would need to use would be
- A.
Twice as great

- B.
The same

- C.
Four times as great

- D.
Half as great

- E.
Cannot be calculated using the given information

- 12.If Elio pushes against an immobile wall with twice as much force as Jordan, which of the following is TRUE?
- A.
Elio is doing twice as much work as Jordan.

- B.
Elio generates twice as much power as Jordan.

- C.
Elio is doing four times as much work as Jordan.

- D.
No work is being done by Elio or Jordan.

- E.
They both generate power in equal amounts.