Posted by **Cathy** on Sunday, February 1, 2009 at 11:07pm.

Problem: A Super Ball is thrown to the ground with an initial downward velocity of 0.70 m/s and pops back up to the hand of the thrower; the total time elapsed is 0.71 s. What height was the Super Ball thrown from?

Do I use the formula x = x0 + v0*t-0.5*g*t^2?

x0=0

v0=-0.70

t=0.71

g=9.81 m/s^2

- Physics -
**drwls**, Monday, February 2, 2009 at 5:06am
Yes, that is the correct equation to use.

1/2 of the 0.71s (0.355s) was spent going down and the other half going back up to the hand.

Let H be the initial height from which it was thrown. It starts at height H at t=0 and reaches height 0 at t - 0.355s

H - 0.70 * 0.355 - 9.81*(0.355)^2 = 0

- Physics (correction) -
**drwls**, Monday, February 2, 2009 at 5:18am
It reaches height 0 at t = 0.355s.

Note that v0 is negative (downward)

H - 0.70 * 0.355 - (9.81/2)*(0.355)^2

= 0

H = 0.249 + 0.618 = 0.867 m

## Answer This Question

## Related Questions

- Physics - A ball is tossed straight up into the air with an initial velocity of...
- Physics - A ball thrown vertically upwards is caught by the thrower 8 seconds ...
- physics - When a ball is thrown upward, it experiences a downward accelera- tion...
- Physic - A ball is thrown vertically upward with a velocity(v) against the ...
- Physics - A ball is thrown towards a vertical wall from a point 2m above the ...
- Physics - A ball is thrown from ground level up in the air at 61m/s. How fast is...
- Physics/Science #3 - A ball is thrown vertically downward from the top of a 35.9...
- Calculus - The height, s, of a ball thrown straight down with initial speed 32 ...
- physics - You and two friends are on top of the library 30 m above the ground. ...
- Physics - A ball is thrown upwards with an initial velocity of 16 m/s. What is ...

More Related Questions