Question

Centrifugal force is an apparent outward force during circular motion. It has been described as a reaction force according to Newton's third law. Which of the following statements is most likely to be correct regarding centrifugal force? A. Centrifugal force exists only for uniform circular motion, not nonuniform circular motion. B. Centrifugal force exists only when tension or a normal force provides centripetal acceleration. C. Centrifugal force always acts antiparallel to the centripetal force vector. D. Centrifugal force is result of repulsive electrostatic interactions.

Short answer

C. Centrifugal force always acts antiparallel to the centripetal force vector.

Step-by-step solution

Understand the Concept of Centrifugal Force

Centrifugal force is an apparent force that acts outward on a body moving around a center, arising from the body's inertia. It acts opposite to the centripetal force, which is the actual force that keeps the body in circular motion.

Analyze the Given Statements

Carefully read each statement provided in the exercise to determine its correctness in relation to centrifugal force.

Examine Statement A

Statement A suggests that centrifugal force exists only for uniform circular motion and not for nonuniform circular motion. However, centrifugal force can be observed in both uniform and nonuniform circular motions as it is perceived due to inertia. Thus, Statement A is incorrect.

Examine Statement B

Statement B suggests that centrifugal force exists only when tension or a normal force provides the centripetal acceleration. However, centrifugal force does not depend on the source of centripetal force; it is an apparent force due to inertia in circular motion. Thus, Statement B is incorrect.

Examine Statement C

Statement C suggests that centrifugal force acts antiparallel to the centripetal force vector. This is correct, as centrifugal force appears to push the object outward while the centripetal force pulls it inward. Hence, Statement C is correct.

Examine Statement D

Statement D suggests that centrifugal force is the result of repulsive electrostatic interactions. This is incorrect, as centrifugal force arises from the inertia of the body in circular motion and is not related to electrostatic interactions.

Determine the Correct Statement

Based on the analysis of the statements, it is evident that Statement C accurately describes centrifugal force as acting antiparallel to the centripetal force vector.

Key concepts

circular motion

Circular motion occurs when an object follows a curved path around a point. This motion can be uniform or nonuniform.
An example of uniform circular motion is a satellite orbiting Earth at a steady speed.
Nonuniform circular motion happens when the speed changes, such as a rollercoaster speeding up or slowing down as it goes around a loop.
Even during uniform circular motion, the direction is constantly changing, meaning the object is always accelerating.
This ongoing change of direction requires a force that constantly pulls the object towards the center of its rotation, known as the centripetal force.

Newton's third law

Newton's third law states that for every action, there is an equal and opposite reaction.
This principle is critical to understanding forces in circular motion.
When a car turns, the friction between the tires and the road provides the centripetal force needed to change direction.
The car 'exerts' a force on the road while the road 'exerts' an equal and opposite force that keeps the car moving in a circular path.
In the context of circular motion, the centrifugal force is often called a 'fictitious' or 'pseudo' force.
It is not a real force but a result of inertia - the tendency of an object to resist changes to its state of motion.

centripetal force

The centripetal force is the real force that acts on an object moving in circular motion.
It pulls the object towards the center of the circle and is necessary to keep the object on its curved path.
This force can come from various sources, such as tension, gravity, or friction.
For example, when you twirl a ball on a string, the tension in the string provides the centripetal force to keep the ball moving in a circle.
Without a centripetal force, an object would move in a straight line due to inertia, as described by Newton's first law.
Centripetal force and centripetal acceleration are always directed towards the center of the circular path.

In summary, centrifugal force is perceived in a rotating reference frame due to inertia and is always directed opposite to the centripetal force.