a proton (m= 1.67 x 20E027kg) that has a speed of 5.0 x 10E6m/s passes thru a metal film of thickness 0.010mm and emerges with a speed of 2.0 x 10E6m/s. how large an average force opposed its motion thru the film?
The Attempt at a Solution
I tried to plug the above equations and nothing works. to be honest I am completely lost. What am I to do? the answer suggests that the force is going N - why if its opposing and its going thru the film it should be going in the opposite direction? Do I use gravity - I have no idea what is expected of me or what they are asking in the first place.
Please help me!