Solve Kinematics Problem: Ball Thrown Upward in Elevator

[Nenad]

hi guyes, I was wondering if someone could help me with a problem I had on a quiz. The question he's been puzzeling me for some time now.

A ball is thrown upward in an open roof elevator traveling at 10m/s(elevator speed). The balls speed is 20m/s. How much time does it take for the ball to reach the same point it was thrown at?

 

[Pyrrhus]

You could use galilean transformations to solve this one, the 10m/s of the elevator must be relative to a inertial frame observer, as the 20m/s. Find the speed relative to the elevator, to simplify calculations.

 

[Doc Al]

A ball is thrown upward in an open roof elevator traveling at 10m/s(elevator speed).

Is the elevator rising or falling?

The balls speed is 20m/s.

I assume that's the ball's speed with respect to the earth/elevator shaft.

How much time does it take for the ball to reach the same point it was thrown at?

I assume you mean same point with respect to the elevator car?

Find the position of the elevator car as a function of time. (Constant speed.)
Find the position of the ball as a function of time. (Constant acceleration.)

Set them equal and solve for the time.