A store clerk pushes a row of shopping carts through the parking lot, accelerating them at 1 m/s?. If the carts have a mass of 300 kilograms, how much force did the clerk put on the carts?

Three air carts have masses reading from left to right of m,2m, and 4m. initially the right cart is at rest while the other twocarts are moving with a speed of Vo. Tall carts have putty bumpersthat give completely inelastic collision. find the final speed ofthe carts.

I am stuck with how to find the final speed of each cart. usingconservation of momentum I got V final to be (3/7 Vo). I amassuming this value to be same for all three carts, but because oneof the cart was at rest I am not sure.

Sorry this is question 84 not 85.

Thanks