Final answer:
The net force exerted on the car is -15 N, which is the result of subtracting the force holding the car stationary (600 N) from the combined pushing force of the individuals (615 N).
Step-by-step explanation:
The question pertains to a scenario in which three individuals are pushing a car against a force that is holding the car stationary.
To determine the net force exerted on the car, we apply Newton's second law of motion and consider the direction of the forces. By convention, we can assign a positive value to the force keeping the car stationary (600 N) and a negative value to the force exerted by the individuals (615 N).
Therefore, the net force is calculated as the sum of these forces: -615 N (negative because it is in the opposite direction) plus 600 N equals -15 N. The negative sign indicates that the net force is in the direction of the individuals' push, but since it's less than the force holding the car stationary, the car will not move forward.