Question

a car is driving on the road. what is the correct relationship of forces acting between the earth and the car?

Explanation:

Step1: Identify forces

The Earth exerts a gravitational force (weight) on the car down - ward, and the car exerts an equal and opposite gravitational force on the Earth according to Newton's third law. Also, the road exerts a normal force on the car upward to balance the weight of the car. The main vertical forces are the gravitational force by the Earth on the car (downward) and the normal force by the road (a part of the Earth - car interaction) on the car (upward).

Step2: Analyze force directions

The gravitational force $\vec{F}_{g}$ exerted by the Earth on the car is downward (towards the center of the Earth), and the normal force $\vec{N}$ exerted by the Earth (through the road) on the car is upward. These two forces act along the vertical direction.

Answer:

The Earth exerts a downward gravitational force on the car and the road (part of the Earth - car system) exerts an upward normal force on the car. The first option (where there are two vertical forces, one upward and one downward) is correct.