Free fall in an accelerating elevator: relative velocity at impact.

If you are in an elevator accelerating downward, how long will it take for a ball to land on the floor, and what's the relative velocity when the ball strikes the floor?

We analyze this problem from two different perspectives. First, we use a stationary "external" reference frame, in which the elevator is accelerating at 3.5m/s^2, and we solve the problem using the standard kinematics equations.

Second, we use an accelerating reference frame (an origin of coordinates that accelerates downward at 3.5m/s^2 along with the elevator). In this reference frame, the acceleration of the elevator is zero, and the acceleration of the ball in free fall on the elevator is reduced by 3.5m/s^2. This reference frame simplifies the kinematics equations at several points, and yields the same answer.

[anthonyduke]

Can you make a more generalized video to show that 2+1/2*acceleration of gravity*t^2=1/2*acceleration of floor*t^2? The conditions that must be met for your problem like the acceleration of gravity always has to be less than the acceleration of the floor. When I saw this I wanted the answers for when the floor was moving the acceleration of gravity down and to show if the floor was moving greater than the acceleration of gravity down the ball will never make it to the floor.

[shun]

Hi I'm kinda beginner in physics stuff, may I ask where is your video explaining about those kinematic formula that you are using? I tried to browse the playlist but can't seems to find an explanation or simple introduction about kinematic formula.