A compact car of mass 1.20×103kg accelerates along a straight, horizontal road. At a particular moment the tires push backward on the road, and the road exerts a 4.00×103N forward frictional force on the tires. At that same moment, resistive forces such as air drag are negligible.
a. Part 1: Identify the pair of interaction forces associated with the 4.00×103N frictional force, clearly specifying the agent and object for each.
b. Part 2: Describe a complete free-body diagram for the car at that instant.
c. Part 3: Determine the car’s acceleration at that instant.
d. Part 4: If the driver chooses to define the system as “car + Earth,” state the net external horizontal force acting on this larger system and explain what that implies about the horizontal motion of the combined system.
e. Part 5: Discuss why the equal and opposite forces identified in Part 1 do not cancel when predicting the acceleration you calculated in Part 3.