**Q9: **

The graph shows how the extension of a spring changes with the force applied to it.

In which region of the graph does the spring have the lowest constant?

- A
- B
- C
- D
- E

In which region of the graph does the spring have the highest constant?

- A
- B
- C
- D
- E

In which region of the graph is the spring constant continuously changing?

- A only
- B only
- C
- D only
- E only

In which region of the graph is the spring’s extension increasing?

- A
- B only
- C only
- D only
- E only

In which region of the graph is only the reversible extension of the spring shown?

- A
- B
- C
- D

In which region of the graph is only the permanent extension of the spring shown?

- A
- B
- C
- D

**Q10: **

The graph shows the length of a spring as the force applied to it changes. What is the spring constant?

**Q11: **

A spring with a mass of 1.6 kg is held horizontally at both ends, and a force of 3 N is exerted at each end. The spring has a constant of 75 N/m. It is then released and returns to its original length. Then, the spring is stretched again, this time with a right-hand force of 4 N and a left-hand force of 2 N.

How far does the spring extend the first time it is stretched?

How far does the spring extend the second time it is stretched?

At what rate does the spring accelerate to the right when it is stretched the second time?

**Q12: **

**Q13: **

A suspended platform is part of the scaffolding around a skyscraper being built. On the platform is a 5 kg mass tool bag suspended from a spring 20 cm long that has a constant of 245 N/m. An accident occurs and the scaffolding structure under the platform suddenly breaks. The platform falls but is slowed as it falls by friction with surrounding scaffolding. The platform drops a distance of 2.5 m, during which its velocity changes from zero to 4.5 m/s, and then comes to rest in a negligible time. What is the length of the spring when the platform has dropped by 2.5 m but not yet come to rest? Round your answer to the nearest centimeter.

**Q14: **

A rocket is launched from Earth, accelerating uniformly. Inside the rocket are control panels, and some of the controls contain springs. A spring in one of the controls that is vertically aligned has a force constant of 555 N/m. The spring is stretched by 2.5 cm under a load with a mass of 1.2 kg.

What is the downward force on the spring? Answer to one decimal place.

What is the rocket’s upward acceleration? Answer to one decimal place.

What was the extension of the spring before the rocket’s launch? Answer to the nearest millimeter.

**Q15: **

The graph shows the length of a spring as the force applied to it changes. What is the magnitude of the spring constant?

**Q16: **

The graph shows the extension of a spring as the force applied to it changes. What is the spring constant?

**Q17: **