# Physics

posted by
**sam** on
.

A 145. drop tower. This is an evacuated vertical tower through which , among other possibilities, a 1m diameter sphere containing an experimental package can be dropped.

a) How long is the sphere in free fall?

b)What is its speed just as it reached a catching device at the bottom of the tower?

c)When caught, the sphere experiences an average deceleration of 25g as its speed is reduced to zero. Through what distance does it travel during the deceleration?

I completly don't understand this question.

which part don't you understand?

For (a), write equation for height (Y) vs. time and solve for the time t when Y=0.

For (b), use V = g t

For c, use the ground-impact velocity V that you get in (b). To decelerate from that velocity within a distance X,

V = sqrt (2 a X)

where a = 25 g

X = V^2/(2 a)