Motion & Projectiles Help Please

  • Thread starter Kotune
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  • #1
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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.
 

Answers and Replies

  • #2
Nugatory
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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.
 
  • #3
21
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That's because you mixed a horizontal speed with a vertical acceleration.

Ah ok I got it now, thanks :).
 

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