The golf club problem was a throwaway – I didn’t expect it to have a long duration. I can’t resist the following plea and will give a formal answer (there is a much simpler way of doing it)
Assume the club has mass M and velcity V and the ball is mass m and velocity v. Momentum must be conserved and, for an elastic collision, so must energy.
Initially:
Momentum: MV
Energy 0.5 M V*V
Afterwards:
Momentum MV’ + mv
Energy 0.5 M*V’*V’ + 0.5 m * v * v
We have the equations:
MV = MV’ + mv
M*V*V = M*V’*V’ + m*v*v
We can reduce the variables by using the ratio of masses (A=M/m) :
A(V – V’) = v
A*(V*V – V’*V’) = v*v
Two equations, 3 unknowns – you will come out with a ratio of velocities. Bit messy. Then let A tend to infinity. You should get a simple answer. Then see if you can find a simpler approach – look at it with a fresh viewpoint –
P.
November 15th, 2006 at 12:02 am eI was hoping someone would pipe up with the answer, because now it’s kind of bugging me. It would seem the standard high school physics doesn’t apply to infinitely massive golf clubs wielded by superbeings. Or if it does, the golf ball flies off at infinite speed and/or blows up in a blinding flash of energy (amounting to it’s mass times the speed of light squared).Put a nerd out of his misery here – what’s the answer?