Suppose a car is traveling at +20.3 m/s, and the driver sees a traffic light turn red. after 0.207 s has elapsed (the reaction time), the driver applies the brakes, and the car decelerates at 7.00 m/s2. what is the stopping distance of the car, as measured from the point where the driver first notices the red light?

Does work output exceed work input when a machine is used? a) yes, it does, as machines create energy. b) it depends on the type of machine used. c) no, it doesn’t, as machines are inefficient. d) no, it doesn’t, as machines cannot create energy.

Mutt and jeff are running along a path each pushing a cart loaded with rocks. if mutt's wagon has a mass two times greater than jeff's and they want to stay together, arriving at their destination at the same time, what must happen? a) jeff should slow down so mutt can catch up. b) mutt must use half as much force to push his cart. c) mutt must use twice as much force to push his cart. d) mutt and jeff will use the same force, but mutt will take bigger steps.

What is the speed of an object at a given moment?