Physics
posted by lily .
A stone is thrown at an angle of 30 degrees above the horizontal from the top of a cliff with an initial speed of 12 m/s. If it hits the ground 4.6 seconds later, what is the height of the cliff?

h=hi=Vi*t4.9t^2 where vi=12sin30, hf=0
hi=4.9t^26t and t=4.6 solve for hi 
59.8 metres