How to Calculate Projectile Motion with Initial Horizontal Velocity

[Kotune]

Homework Statement

A night somebody pushes a derelict car horizontally off a 45m high cliff top at 2.0 ms^-1.
(a) How long does it take to hit the ground? (g=10ms^-2)
(b) How far from the base of the cliff does it land?

Homework Equations

The answer to (a) is 3.0s and (b) is 6.0m

The Attempt at a Solution

For (a) I tried s = ut +.5at^2. Hence 45 = 2t+.5(10)t^2 but the answer was not correct.

 

[Nugatory]

For (a) I tried s = ut +.5at^2. Hence 45 = 2t+.5(10)t^2 but the answer was not correct.

That's because you mixed a horizontal speed with a vertical acceleration.

 

[Kotune]

That's because you mixed a horizontal speed with a vertical acceleration.

Ah ok I got it now, thanks :).