Question

A car's engine provides a driving force of 30N. The car travels at a steady speed of 20m/s. What is the size of the resistive force acting against the driving force?

Answer 1

The right answer is "30 N"

Answer explanation:

If a car is travelling at a steady speed, the resultant force must be zero, so the driving force and resistive force must be equal and opposite.

Hope it helps

Answer 2

30 N

Step-by-step explanation:

Since the car travels at a steady speed of 20m/s and has a driving force of 30N, there is no net acceleration and thus, the resistive force is also 30 N in magnitude but in the opposite direction to the driving force. This is shown below.

F - f = f' where F = driving force = 30 N. f = resistive force and f'= net force.

f' = 0 since there is no acceleration. So,

F - f = 0

F = f = 30 N