1. The problem statement, all variables and given/known data For our lab we had to find the coefficient of kinetic friction for a cart on a linear track. We pushed the cart on the track and it went through two photogates which measured the time it spent in the photogate. So through the 1st photogate = 0.0040s 2nd photogate = 0.0062s There was a flag on the cart which was 0.42cm. So we found the instantaneous velocity through the first gate as v=0.0042m/0.0040s = 1.05m/s The instantaneous velocity through the second gate was v=.0042m/.0062s = 0.677m/s The mass of the cart is = 0.507 kg 2. Relevant equations vf = vo + at F=ma Ff = ukFN FN = mg 3. The attempt at a solution I was going to use vf = vo + at find the acceleration as a= vf - vo/t but I don't know what the time is between the change instantaneous velocity. I know if I get the acceleration I can plug into the F=ma, find the force and somehow get the frictional force from there.