3. You are studying the effect of the force of a rubber band on Force (N) your friend sitting in a shopping cart. You have fixed the 125 kg cart (cart with your friend and groceries) with a rubber band 3000- to the shelf with the dog food and push your friend and the cart away from the shelf with a speed of 5.0 m/s. The force versus 2000 time curve for the rubber band is shown in the figure. 1000 a. At what speed is the cart with your friend rolling back towards the shelf? 0 0.4 0.8 1.2 1.6 b. Is your result reasonable? Time (s)