Homework Help: Projectile Motion Golf Question

1. Jul 5, 2011

michaeljf

1. The problem statement, all variables and given/known data
Not too long ago, an interesting thing happened at the Canadian Open Golf Tournament. Tiger Woods bounced his tee shot off of a young spectator’s head in the last round of the tournament. The ball made contact for 0.08 seconds, and struck the boy’s head at a velocity of 32 m/s, 25degree from a tangent on the surface of his cranium. It bounced off at an angle of 22degree, with a speed of 25 m/s. What was the average acceleration of the ball as it amazingly made its way back onto the fairway?

I have no idea on how to start this.

2. Relevant equations

3. The attempt at a solution

2. Jul 5, 2011

ideasrule

What's the difference between the final velocity of the ball and its initial velocity? Remember that acceleration is just change in velocity divided by change in time.

3. Jul 5, 2011

Delphi51

Welcome to PF, Michael.
Not a particularly clear question! I would be tempted to answer that the acceleration is -9.81 m/s² as it "makes its way back onto the fairway" but I suppose the question really means the acceleration while in contact with the boy's head. There are 2D directions involved so you need a diagram sorting out those angles and you need to calculate the acceleration in each of the two dimensions and then get a combined value. Just use a = Δv/Δt.

4. Jul 5, 2011

michaeljf

I thought in projectile motion, the horizontal velocity does not change, thus a = 0 and its 9.81 for the vertical component?

5. Jul 6, 2011

Delphi51

That's true for the free flight (neglecting air resistance).
But my theory is that you are asked for the acceleration when the head is exerting a force on the ball. I haven't drawn the diagram, but since the angle with the head changes, I suspect the ball changes speed in both the direction perpendicular to the head and the direction parallel to it.