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**Help me do this assignment. My grade depends on it! *Cure a high schooler's anxiety***

**1.I am stuck on these 12 questions. The given data and equations are provided in each question.**

**2. 1. A bowling ball hangs from a 2-meter rope attached to the ceiling. Keeping the rope taut, you pull the ball up until the rope makes an angle of 60° with respect to the vertical. You let the ball go. About how fast will it be moving at the bottom of the swing?**

Cannot be determined without the mass of the ball.

4.5 m/s

6.3 m/s

3.2 m/s

5.9 m/s

2. A brick is dropped from a second story window. Next, a second brick, which weighs twice as much as the first brick, is dropped from the same window. When the second brick strikes the ground it has...

Half as much KE as the first brick.

Same KE as the first brick.

Twice as much KE as the first brick.

Four times as much KE as the first brick.

Not enough information to compare KE's.

3. An engine delivers 32 hp. About how long will it take for the engine to do 700 kJ of work? Remember, 1 hp = 746 W.

0.03 s

0.3 s

3 s

30 s

300 s

4. Kiera carries a 5-kg box up the stairs. If the second floor is 4 meters above the first, about how much work does Kiera do on the box? Give your answer in Joules.

5

20

200

Not enough information to calculate the work.

40

5. Kyle has to move a 1500-N piano onto a porch 1.2 meters above the ground. He finds a board to use as a ramp and rolls the piano up to the porch. What average force was needed if the ramp was 3.1 meters long? Give your answer in Newtons and neglect friction.

484

581

750

3880

5810

6. Consider the energy transitions that occur during a pole-vault event. Disregard rotational motion and air resistance. Choose the best energy description for each given action. Make a number selection for each letter:

1)Min. KE, max grav. PE

2)All KE

3)KE decreases, elastic PE increases

4)All elastic PE

5)KE and elastic PE decrease, Gravitational PE increases

6)Grav. PE decreases, KE increases

a.The pole vaulter moves down the runway.

b.The pole vaulter plants the end of his pole into the box. He slows and the pole bends.

c.The pole vaulter leaves the ground. He goes up, slowing and unbending his pole

d.The pole vaulter clears the bar.

e.Having cleared the bar, the pole vaulter is falling toward the pit.

7. The PE of an object in Earth's gravitational field can be written as:

PEgrav=-G*Mearth*(m/r)

Where is the potential energy equal 0?

Choose one answer.

When r = 0.

When r = the radius of the earth.

When r is very small but not 0.

When r very large, approaching infinity.

When r = the radius of the Earth + 300,000 meters. 8. A marble rolls down a ramp that sits on table. The marble leaves the base of the ramp with a horizontal velocity. The base of the ramp is 2 meters above the floor. The marble strikes the floor at a distance of 1.8 meters from where it left the ramp. Give the height of the ramp with respect to the floor.

Choose one answer.

2.4 m

0.4 m

4.4 m

1.4 m

2.2 m

9. In which situation described below is Taylor positive work?

Choose one answer.

He pushes on the wall which does not move.

He carries a book across the room at a constant height.

Losing at tug-a-war, he is pulled toward his opponent.

He ties a rope to an object and swings it in a horizontal circle at a uniform rate.

He walks up the stairs. 10. The units for power are...

Choose one answer.

Newton

Pascal

Joule

Watt

None of these

11. A spring with stiffness coefficient K = 9 N/cm is stretched 20 cm. Measured in Joules, the elastic potential energy is ...

Choose one answer.

18

36

90

900

1800

12. If a pole vaulter moves at 8.0 m/s down the runway, what is the maximum height that she can clear?

Choose one answer.

3.2 m

32 m

6.4 m

8 m

1.6 m

Cannot be determined without the mass of the ball.

4.5 m/s

6.3 m/s

3.2 m/s

5.9 m/s

2. A brick is dropped from a second story window. Next, a second brick, which weighs twice as much as the first brick, is dropped from the same window. When the second brick strikes the ground it has...

Half as much KE as the first brick.

Same KE as the first brick.

Twice as much KE as the first brick.

Four times as much KE as the first brick.

Not enough information to compare KE's.

3. An engine delivers 32 hp. About how long will it take for the engine to do 700 kJ of work? Remember, 1 hp = 746 W.

0.03 s

0.3 s

3 s

30 s

300 s

4. Kiera carries a 5-kg box up the stairs. If the second floor is 4 meters above the first, about how much work does Kiera do on the box? Give your answer in Joules.

5

20

200

Not enough information to calculate the work.

40

5. Kyle has to move a 1500-N piano onto a porch 1.2 meters above the ground. He finds a board to use as a ramp and rolls the piano up to the porch. What average force was needed if the ramp was 3.1 meters long? Give your answer in Newtons and neglect friction.

484

581

750

3880

5810

6. Consider the energy transitions that occur during a pole-vault event. Disregard rotational motion and air resistance. Choose the best energy description for each given action. Make a number selection for each letter:

1)Min. KE, max grav. PE

2)All KE

3)KE decreases, elastic PE increases

4)All elastic PE

5)KE and elastic PE decrease, Gravitational PE increases

6)Grav. PE decreases, KE increases

a.The pole vaulter moves down the runway.

b.The pole vaulter plants the end of his pole into the box. He slows and the pole bends.

c.The pole vaulter leaves the ground. He goes up, slowing and unbending his pole

d.The pole vaulter clears the bar.

e.Having cleared the bar, the pole vaulter is falling toward the pit.

7. The PE of an object in Earth's gravitational field can be written as:

PEgrav=-G*Mearth*(m/r)

Where is the potential energy equal 0?

Choose one answer.

When r = 0.

When r = the radius of the earth.

When r is very small but not 0.

When r very large, approaching infinity.

When r = the radius of the Earth + 300,000 meters. 8. A marble rolls down a ramp that sits on table. The marble leaves the base of the ramp with a horizontal velocity. The base of the ramp is 2 meters above the floor. The marble strikes the floor at a distance of 1.8 meters from where it left the ramp. Give the height of the ramp with respect to the floor.

Choose one answer.

2.4 m

0.4 m

4.4 m

1.4 m

2.2 m

9. In which situation described below is Taylor positive work?

Choose one answer.

He pushes on the wall which does not move.

He carries a book across the room at a constant height.

Losing at tug-a-war, he is pulled toward his opponent.

He ties a rope to an object and swings it in a horizontal circle at a uniform rate.

He walks up the stairs. 10. The units for power are...

Choose one answer.

Newton

Pascal

Joule

Watt

None of these

11. A spring with stiffness coefficient K = 9 N/cm is stretched 20 cm. Measured in Joules, the elastic potential energy is ...

Choose one answer.

18

36

90

900

1800

12. If a pole vaulter moves at 8.0 m/s down the runway, what is the maximum height that she can clear?

Choose one answer.

3.2 m

32 m

6.4 m

8 m

1.6 m

**3. I have attempted each question but energy transformations are almost impossible for me.**