Question

You have a ball with mass 2.8 kg tied to a rope, and you spin it in a circle of radius 1.3 m. If the ball is moving at a speed of 7 m/s, what is the centripetal force acting on the ball?

Answer 1

According to Newton's second law:

F=ma=m*v^2/R=2.8*7^2/1.3=105.54 N

Answer 2

Centripetal force;

$= \frac{m {v}^{2} }{r}$

$= \frac{2.8 \times {7}^{2} }{1.3}$

$= \frac{2.8 \times 49}{1.3} \\ \\ = \frac{137.2}{1.3} = 105 \: newtons$