Question

A particle does uniform circular motion in a horizontal plane. The radius of the circle is 20 cm. The centripetal force acting on the particle is 10 N. It’s kinetic energy is

• A. 0.1 Joule
• B. 0.2 Joule
• C. 2.0 Joule
• D. 1.0 Joule

Answer 1

Answer: (D)

1.0 Joule

Answer 2

$\frac{mv^{2}}{r} = 10N$ (given) ⇒ $mv^{2} = 10 \times r$ $= 10 \times 0.2 = 2$

Kinetic energy $\frac{1}{2}mv^{2} = \frac{1}{2}(2) = 1Joule.$