A car moves with uniform velocity of 40m/s for 5 s. It comes to rest in the next 10 s with uniform deceleration

With i really need the correct answer!

Simple machines can a. increase force only b. decrease force only c. increase or decrease force

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.