Question

How would you measure the speed of ball rolling on a floor?

Answer 1

My way of thinking:

Because the collision lasts is "very short" the force acting perpendicular to the surface of the wall on the ball is very large. Thus so is the friction. Thus the inertia is transformed into vertical motion. This would mean no matter the speed the ball would move up. This doesn't seem to be a correct answer though.

Answer 2

I will see the speed of ball in 30s and how many time it may cover distance and when I got all things so I will multiple by required time