A 4.00 kg mass is moving in a circular path of radius 3.20 m with a constant linear speed of 6.20 m/s. The radial force on the mass is
A) 40.2 N away from the center.
B) 48.1 N toward the center.
C) 50.5 N away from the center.
D) 59.0 N toward the center.
E) 62.3 N away from the center.

Question

Quizplus · Accepted Answer

The radial force on the mass is given by $F_r=m \frac{v^2}{r}$, where $m$ is the mass of the object, $v$ is the speed, and $r$ is the radius of the circular path. Plugging in the given values, we get $F_r = (4.00 kg)\frac{(6.20 \frac{m}{s})^2}{3.20 m} = 48.1 N$ which is toward the center of the circle (since it is a centripetal force). Therefore, the best choice is B.

A 400 Kg Mass Is Moving in a Circular Path of of Radius