Posted by **.** on Tuesday, October 5, 2010 at 1:10pm.

Can anyone answer part 3 for me? I've tried so many incorrect answers that I've already given up: 1.00, 1.50, 2.00, 3.00, 9.40

Question: A slingshot obeying Hooke's law is used to launch pebbles vertically into the air. You observe that if you pull a pebble back 2.00 cm against the elastic band, the pebble goes 3.00 m high.

Part A (already answered correctly): Assuming that air drag is negligible, how high will the pebble go if you pull it back 5.00 cm instead? Answer: h = 18.8 m

Part B (already answered correctly): How far must you pull it back so it will reach 13.0 m? Answer: x = 4.16 cm

Part C: If you pull a pebble that is twice as heavy back 3.00 cm, how high will it go? Answer: h = ___ cm

- Physics -
**bobpursley**, Tuesday, October 5, 2010 at 1:14pm
given 3m high, at 2cm pull.

OK, you are pulling it 50 percent more, and doubling mass.

doubling mass will halve the height (PE=mgh)

The PE in the elastic goes by 1/2 k x^2, so if you increase the x to 1.50, that squared is 2.25x, so

doubling mass, pulling to 3cm, should make height 3m*1/2*2.25

## Answer This Question

## Related Questions

- Physics - If a 40 kg brick and a 400 kg brick each dropped from 1 m above a ...
- Physics - 1. A slingshot is used to launch a 5.00-gram rock. The effective ...
- physics - A boy uses a slingshot to launch a pebble straight up into the air. ...
- physics - A ball bounces to 34 percent of its original height. *1) What fraction...
- Physics - 2 students ride a slingshot. The slingshot catapults 2 students at a ...
- Physics - All answers should be in degrees. (a) Using the result of Lecture 31 ...
- Physics - If a 40 kg brick and a 400 kg brick each dropped from 1 m above a ...
- @ elena - intro to physics - I posted this question earlier and thank you for ...
- Physics - f a 40 kg weight and a 200 kg weight each dropped from 1 m above the ...
- Physics - I launch a ball vertically precisely 8' in the air. Then I launch a ...

More Related Questions