- #1
Ailo
- 17
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Homework Statement
A person standing at the top of a hemispherical rock of radius R kicks a ball (initially at rest on the top of the rock) to give it horizontal velocity vi
(a) What must be its minimum initial speed if the ball is never to hit the rock after it is kicked?
(b) With this initial speed, how far from the base of the rock does the ball hit the ground?
Homework Equations
[tex]\frac{1}{2}gt^2=R=y, \ v_it=x, \ (v^2/R=a_c ?)[/tex]
The coordinate system I use is one with a horizontal x-axis in the direction of the kick and a vertical y-axis downwards.
The Attempt at a Solution
Basically, I just tried gathering as much information as possible. I got [tex]t=\sqrt{2R/G}[/tex]. I also managed to link x and the initial speed in an equation: [tex]gx^2=2v_i^2R[/tex]. But I'm stumped as to how I can assure that the ball doesn't hit the rock. Maybe I have to use what I know about circular motion as well, but that's just a wild guess... Any hints? =)