# physics

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You're on a magic bridge floating 25 meters above a lake.  You through a rock at an angle of sixty degrees.  It takes 5.8 seconds for the rock to reach it's highest point.

(a)  With what speed did you throw the rock?
(b)  How far away from the bridge horizontally did the rock land?

• physics -

sixty degres measured how?

• physics -

Measured to the horizontal

Throw*

• physics -

Then the vertical velocity initial is Vsin60.

At the top, vertical velocity is zero.

Vtop=Vivertial-gt
so time to top= Vivertial/g=Vsin60 /g
then solve for V

Now how far: You have to find vertical time in air.
hf=hi+Vivertical*t-1/2 g t^2
0=23+Vsin60* t-1/2 g t^2

solve for t, time in air. Use the quadratic formula.

Now distance: distance= Vhoriz*timeinair
where vhoriz= Vcos60

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