PDA

View Full Version : Static Friction and calculating distance


californiadaisy
Oct22-06, 08:31 PM
Brad is sitting at rest on a wheeled chair in a long hallway. He and the chair have a combined weight of 540 N. His friend throws a 15 kg medicine ball horizontally at Brad with a velocity of 6 m/s. Brad cataches the medicine ball. If the coefficient of static friction between the chair wheels and the floor is 0.05, how far will Bard travel after catching the ball?

My prof said that this is a combination problem meaning that multiple laws of phyics are going to be used. My problem is that I can't tell which laws I need to be using. Any help would be greatly appreciated.

Thanks!

OlderDan
Oct22-06, 11:10 PM
Brad is sitting at rest on a wheeled chair in a long hallway. He and the chair have a combined weight of 540 N. His friend throws a 15 kg medicine ball horizontally at Brad with a velocity of 6 m/s. Brad cataches the medicine ball. If the coefficient of static friction between the chair wheels and the floor is 0.05, how far will Bard travel after catching the ball?

My prof said that this is a combination problem meaning that multiple laws of phyics are going to be used. My problem is that I can't tell which laws I need to be using. Any help would be greatly appreciated.

Thanks!
It is a two-step problem. First, momentum is conserved; Brad acquires a velocity in the process. He and the ball are then moving, but are slowed to a stop by a frictional force. This second part can be approached in a couple of different ways to find the distance moved.