Question

A $0.5\, kg$ ball moves in a circle of radius $0.4\, m$ at a velocity of $4\, m / s$. The centripetal force on the ball is

• A. 10 N
• B. 20 N
• C. 40 N
• D. 80 N

Answer 1

Answer: (B)

20 N

Answer 2

$F=\frac{m v^{2}}{r}$ $F=\frac{0.5 \times 4 \times 4}{0.4}$ $F =\frac{8.0}{0.4}$ $=\frac{80}{4}=20\, N$