Motion problem - Shock drop ride

1. The problem statement, all variables and given/known data
a ride at a them park is a vertically ascending/decending ride. The total mass of the 10 person carriage is 750kg (people included). the ride rises up to the top of the ride until stationary waits for 2 seconds and then drops at a rate of 10ms-2 for 3.5m. when near the bottom of the ride, the carriages brakes are applied for 0.8m.

a) how long is the carriage in freefall until the brakes are applied?
2. Relevant equations
not too sure, but i think you'll probably require:
v=u+at
s=1/2(u+v)t

3. The attempt at a solution
to be honest, i have no idea where to begin
thanks

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 hello,I suppose you'ld not need most of the data given. We can assume $$g=10ms^{-2}$$ now we know distance covered,the acceleration,the initial velocity. Just put in formulas

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