# Physics

You throw a baseball at a 45∘ angle to the horizontal, aiming at a friend who's sitting in a tree a distance h above level ground. At the instant you throw your ball, your friend drops another ball. The two balls will collide, no matter what your ball's initial speed, provided it's greater than some minimum value. Find an expression for that minimum speed.

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1. well, it is of such minimum speed that it must reach at least a horizontal distance directly below the friend.

If you are stuck with the 45 degree angle, then
distance=vcos45*time
timeinair=distance/vucos45

but in the vertical...
vf=viSin45*t-gt or
but if no energy is lost, vf=-visin45 so
-viSin45=visin45-g(distand/vucos45)
so solve for Vi.

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