Final answer:
Pushing on the steering wheel of a car does not cause acceleration because it's an internal force; external forces are needed to alter a car's motion according to Newton's laws.
Step-by-step explanation:
Sitting in your car and pushing on the steering wheel will not cause your car to accelerate because you are not exerting an external force on the car. When considering the real world connections between work and direction, it's important to understand the interactions of forces involved in the acceleration of an object. If you're sitting in a car, any force you apply by pushing on the interior of the car, such as the steering wheel or dashboard, is an internal force. Internal forces cannot cause the car's center of mass to accelerate relative to the ground because they do not result in a net force on the system as a whole.
External forces, such as the thrust from an engine or friction from brakes acting on the wheels, are required to change the car's kinetic energy—be it to accelerate, decelerate, or change direction. Newton's laws of motion explain how these external forces affect motion. For example, a car turning a corner experiences a change in direction, and thus an acceleration, as a result of an external force exerted by the friction between the tires and the road.