If the car were to abruptly stop and the seat belts were not being worn, then the passengers in motion would continue in motion. Assuming a negligible amount of friction between the passengers and the seats, the passengers would likely be propelled from the car and be hurled into the air.

force equals mass times acceleration. In this case, the acceleration is (v – 0)/t, where t is whatever time it takes car A to come to a stop. The car exerts this force in the direction of the wall, but the wall, which is static and unbreakable, exerts an equal force back on the car, per Newton’s third law of motion.

frictional force

A passenger jumping out from a rapidly moving bus or train is advised to jump in forward direction and run forward for a short mile due to inertia of rest. When a running bus or train stops suddenly, the passengers sitting in it jerk in forward direction due to the inertia of motion.

If a moving body comes to rest, then its acceleration is negative, as it’s velocity becomes zero. therefore the acceleration is also zero.

Rolling friction is equal to sliding friction.

If there were no friction, work need to be done to move a body up an inclined plane is zero. If there were no friction, moving vehicles could not be stopped even by locking the brakes. As the angle of inclination is increased, the normal reaction on the body placed on it increases.

Normal reaction is also independent of area of contact. So, we can say that friction force is independent of area of contact. So “Frictional force is proportional to the area of contact between the surfaces” is wrong statement.

Hence, the correct answer for the question is option C. Note: It may be important to note that static friction is a variable force whereas kinetic friction and rolling friction are constant forces for two given bodies.

Complete step by step answer: As friction is an opposing force it resists the motion when two surfaces come in contact with each other. A) Frictional force can accelerate a body: Frictional force can cause acceleration but it would be in the opposite direction of the motion.

Friction is a contact force when two surfaces interact. Notice that both of these friction formulas ONLY depend on the coefficient of friction and the normal force. It does not depend the area of contact, it doesn’t depend on the sliding speed.