Physics - Kinematics

Audi SG

A liftis moving down with an acceleration of 3 m s-2. A ball is released 1.7m above the lift floor. Assuming g = 9.8 ms -2, how long will the ball take to hit the floor?

I do know how to solve this but before that I had to find the acceleration of ball relative to life, and taking upwards direction as +ve,

Acc = -9.81 +3 = -6.81 m s-2

Can someone explain this to me? Thanks. Always had trouble understanding acceleration in a lift and not sure if the acc. is upwards/downwards since lift moves up and down. LOL.

eagle SG

If g was zero,

the relative acceleration of the ball w.r.t. the lift is 3 ms-2 downwards right?

Another scenario,

if acceleration of the lift downwards was 9.81 ms-2, then the relative acceleration of the ball w.r.t. the lift is zero right?

Ask yourself it is possible for the ball to be accelerating downwards faster than 9.81 due to g-force w.r.t. the lift when the lift is falling at the same time....