Posted by **Jessica** on Friday, February 17, 2012 at 11:06am.

A 3-kg stone is dropped from a height of 100 m. Find its kinetic and potential energies when it is 50 m from the ground.

- Physical Science -
**Henry**, Saturday, February 18, 2012 at 7:52pm
PE = mgh = 3 * 9.8 * 100 = 2940 J.

Vf^2 = Vo^2 + 2g*d,

Vf^2 = 0 + 19.6*50 = 980,

Vf = 31.3 m/s.

KE = 0.5m*V2 = 1.5*(31.3)^2 = 1470 J.

PE = 2940 - 1470 = 1470 Joules.

- Physical Science -
**Jessica**, Sunday, February 19, 2012 at 12:43pm
Where did you get the 19.6 from?

Also what formula are you using? The Vf^2 = Vo^2 + 2g*d....i've never seen that before

## Answer This Question

## Related Questions

- Intro to Physical Science - A 3-kg stone is dropped from height of 100 m. Find ...
- science(physics) - A 2kg stone is droped from the top of a 20m building a)what ...
- physics - a stone of mass o.5 kg is dropped from a height of 5om.what is the ...
- physics - a stone of mass o.5 kg is dropped from a height of 5om.what is the ...
- physics - A stone is thrown straight up from the ground with an initial speed of...
- science - A bouncy rubber ball is dropped from a height of about a metre above ...
- Physics - A Stone Of Mass 1kg Is Dropped From Rest From A Window 20m Above The ...
- Physics - A stone is dropped from a ballon while ascending at the rate of 8mps. ...
- physics - a stone is dropped from arising balloon at a height of 76m above the ...
- physics - A stone is thrown straight up from the ground with an initial speed of...

More Related Questions