***PLEASE ANSWER ALL FOUR***

1) A car is waiting at a stoplight. The car has a mass of 1200 kg. What is the force (magnitude and direction) that the road puts on the wheels?

***Note that problems 2, 3 and 4 ask for the force of friction only, not the normal force.***

2) The same car accelerates out of the stoplight at 1.5 m/s 2 . Draw a free-body diagram of the car and find the force of friction (magnitude and direction) that the road puts on the wheels.

3) The same car reaches a top speed of 15 m/s, then begins braking. It comes to a halt in 20 seconds. Draw a free body diagram of the car and find the force of friction (magnitude and direction) that the road makes on the wheels now.

4) The same car is now towing a 200kg trailer. It accelerates out of the stoplight a little slower, at 0.8 m/s 2 . Draw free-body diagrams of the car and the trailer as it accelerates. What is the force of friction that the road makes on the car wheels now?