An object of mass 2 kg moves with a velocity of 10 ms1 round at circle of radius 4 m. Calculate the centripetal force on the object

Analyze the question: An object of mass 2 kg moves at 10 m/s in a circle of radius 4 m. We need the centripetal force.

Concept: The centripetal force is the inward force that keeps an object moving in a circle:

F = mv²/r

where m is mass, v is speed and r is the radius of the circle.

Solution:

• m = 2 kg
• v = 10 m/s
• r = 4 m

F = (2 × 10²) / 4 F = (2 × 100) / 4 F = 200 / 4 F = 50 N

Answer: The centripetal force is 50 N, which is option C.

Tip: Square the velocity before you multiply or divide. Many students compute 2 × 10 = 20 and then square it, or forget to square v at all. If you forget the square, you get 2 × 10 / 4 = 5 N, which is not among the options. Remember "mv² over r" and check your units: kg × m²/s² ÷ m = kg·m/s² = N.