Question 1

What is centripetal force?

Accepted Answer

Centripetal force is the net force directed toward the center of a circular path that keeps an object moving in a circle. It is not a new type of force, but rather the name for whatever force provides the inward pull, such as tension in a string, gravity for orbiting bodies, or friction for a car turning a corner.

Question 2

What is the difference between centripetal and centrifugal force?

Accepted Answer

Centripetal force is the real inward force that causes circular motion. Centrifugal force is a fictitious (or pseudo) force that appears in a rotating reference frame. From the perspective of a passenger in a turning car, it feels like they are being pushed outward (centrifugal), but in reality, the car seat is pushing them inward (centripetal).

Question 3

Why does centripetal force depend on velocity squared?

Accepted Answer

As an object moves faster in a circle, it needs to change direction more rapidly, requiring a stronger inward force. The v² dependence means doubling the speed quadruples the required centripetal force. This is why sharp turns at high speed are dangerous.

Question 4

What provides centripetal force for planets orbiting the Sun?

Accepted Answer

Gravity provides the centripetal force for planetary orbits. The gravitational pull of the Sun keeps planets moving in approximately circular (actually elliptical) paths. Setting the gravitational force equal to centripetal force (GMm/r² = mv²/r) allows you to derive orbital velocities and periods.

Centripetal Force Calculator (F = mv²/r)

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