Im studying on my own and dont have the benefit of input from an instructor, so any help with these few questions would be very appreciated. 1. If a car traveling at a constant velocity has a net force of 0, why can it be said that work is being done on the car when Work equals force multiplied by distance? 2. A golf ball is thrown at and bounces off a very massive bowling ball that is initially at rest. Which ball, after impact has greater momentum, and which has greater kinetic energy? On question two, I think the answer is the bowling ball has greater momentum, since the golf ball changed velocity double what it would have relative to the bowling ball if it had not bounced, and since momentum is conserved, twice the momentum would be imparted into the bowling ball in order for net momentum = 0. And since KE=.5mv^2, I would think the golf ball would have more kinetic energy, having a much higher velocity. Am I correct here, or am I missing something. Thanks.