What is centripetal force?

What is centripetal force?

• A. Toward the axis of rotation
• B. Toward the center
• C. Toward the circumference
• D. Perpendicular to velocity

Answer: (B)

In circular motion, the object needs a net inward force toward the center to keep following the curved path. That inward pull is centripetal force. It points toward the center of the circular path, since that’s the direction required to produce the inward (centripetal) acceleration a_c = v^2 / r. The magnitude depends on the mass, speed, and radius: F = m v^2 / r, and the actual force can come from gravity, tension, friction, or normals depending on the situation. Why the inward direction is the right description: pulling toward the center keeps the motion curved rather than flying off in a straight line. Descriptions like toward the circumference describe outward motion, which isn’t the centripetal force. Describing it as perpendicular to velocity is a property in uniform circular motion, but the defining characteristic is the inward direction toward the center.

In circular motion, the object needs a net inward force toward the center to keep following the curved path. That inward pull is centripetal force. It points toward the center of the circular path, since that’s the direction required to produce the inward (centripetal) acceleration a_c = v^2 / r. The magnitude depends on the mass, speed, and radius: F = m v^2 / r, and the actual force can come from gravity, tension, friction, or normals depending on the situation.

Why the inward direction is the right description: pulling toward the center keeps the motion curved rather than flying off in a straight line. Descriptions like toward the circumference describe outward motion, which isn’t the centripetal force. Describing it as perpendicular to velocity is a property in uniform circular motion, but the defining characteristic is the inward direction toward the center.