Centripetal Force Examples in Physics

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Centripetal Force.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Physics.

Concept Recap

The net inward force required to keep an object moving along a circular path, directed toward the centre of the circle, equal to mv^2/r where no new type of force is created.

The force that pulls you toward the center when you go around a curve.

Read the full concept explanation →

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Centripetal force is not a new type of force—it's whatever force happens to point toward the center.

Common stuck point: 'Centrifugal force' is fictitious—it's just inertia trying to go straight.

Sense of Study hint: When solving a centripetal force problem, first identify what physical force provides the centripetal force (gravity, tension, friction, normal force). Then set that force equal to mv^2/r and solve for the unknown. Finally, remember that centripetal force is not a new force — it is the net inward force that causes circular motion.

Worked Examples

Example 1

medium
A 0.5 \text{ kg} ball on a 1.2 \text{ m} string is swung in a horizontal circle at 4 \text{ m/s}. What is the centripetal force?

Solution

  1. 1
    Recall the centripetal force formula: F_c = \frac{mv^2}{r}, where m is mass, v is speed, and r is radius.
  2. 2
    Identify the given values: m = 0.5 \text{ kg}, v = 4 \text{ m/s}, r = 1.2 \text{ m}.
  3. 3
    Substitute and calculate: F_c = \frac{0.5 \times 4^2}{1.2} = \frac{0.5 \times 16}{1.2} = \frac{8}{1.2} \approx 6.67 \text{ N}

Answer

F_c \approx 6.67 \text{ N}
Centripetal force is the net force directed toward the center of the circular path. It is provided by the string tension in this case and keeps the ball moving in a circle.

Example 2

hard
A car of mass 1000 \text{ kg} rounds a curve of radius 50 \text{ m}. If the maximum static friction force is 8000 \text{ N}, what is the maximum safe speed?

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

medium
A satellite orbits Earth at radius r = 7 \times 10^6 \text{ m} with speed v = 7500 \text{ m/s}. What is the centripetal acceleration?

Example 2

medium
A 0.25 \text{ kg} ball moves in a circle at 6 \text{ m/s} and experiences a centripetal force of 9 \text{ N}. What is the radius of the circle?
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Background Knowledge

These ideas may be useful before you work through the harder examples.

circular motionforce