Posted by **Keith** on Tuesday, January 25, 2011 at 4:21pm.

a girl throws a ball vertically upwards at 5m/s from the roof of a building 20m high

how long will it take the ball to reach the ground? and what will its speed be when it strikes the ground

- physics -
**bobpursley**, Tuesday, January 25, 2011 at 4:27pm
when at the top, vertical velocity is zero

vf=0=vi+gt solve for t, time to top.

How long it will take to get to the ground?

Hf=Hi+vi*t-1/2 g t^2 hi=20, hf=0, solve for t to get time in the air.

## Answer this Question

## Related Questions

- physics, please help me, this question is hard - John Stands at the edge of a ...
- physics - A 3.00 kg ball is dropped from the roof of a building 176.4 m high. ...
- physics - a ball is dropped off a 20m high building, the ball weights 5 g. how ...
- science - A boy standing on top a building with a height of 500m throws a ball ...
- physics - A ball is thrown vertically up from the edge of a 150 m building with ...
- Physics - A ball is thrown upwards, from a building. It's height(h), in meters ...
- 11 Physics - my teacher gave me this question for review and i don't know how to...
- Physics - A 2.98 kg ball is dropped from the roof of a building 158.3 m high. ...
- Physics please help!!!!!!! - A ball is thrown vertically upward (assumed to be ...
- physics - HELP ASAP! - A 3.60 kg ball is dropped from the roof of a building 184...

More Related Questions