- #1

Naeem

- 194

- 0

**Ball in Elevator...**

Q.

Ball in Elevator

--------------------------------------------------------------------------------

A physicist is inside an elevator rising in a skyscraper. She is holding a ball at a height h = 2.1 m above the floor of the elevator.

--------------------------------------------------------------------------------

a) She let's go of the ball while the elevator is rising at a constant speed of 4.6 m/s. How long does it take the ball to hit the elevator floor?

tto floor = s

2.1/4.6 NO

HELP: The ball and the elevator floor will be at the same height above the ground when the ball hits the floor

I used

x - x0 =v0t + 1/2at^2

Since constant speed acc. is zero.

so,

t = x-xo/vo

2.1 /4.6 which is wrong?

Any one help

--------------------------------------------------------------------------------

b) Now let's try a somewhat harder variation on this problem. Suppose instead that the elevator is accelerating upward with constant acceleration a = 1.2 m/s2 and that the upward speed of the elevator at the instant the ball is dropped, is 4.6 m/s. Now how long does it take the ball to hit the elevator floor, assuming once again that it is dropped from a height of 2.1 m? Q

No idea here help me, what equations, may be the same one as above, what to plugin, etc.etc.