physics
posted by stacy .
A rock is thrown from a cliff top at 18m/s, 25 degrees above the horizontal. It lands on the beach 4.2 seconds later.
a) What is the height of the cliff?
b) Hor far from the base of the cliff did the rock land?

vertical veloctiy: 18sin25
Hf=hi+viv*t1/2 g t^2
hf=0, hi=unknown,viv=18sin25, t=4.2 solve for hi.
horizontal distance? 18cos25*4.2 
great, thank you so much!

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