question_answer

A body of mass 5 kg is moving in a circle of radius 1 m which an angular velocity of 2 rad/s. The centripetal force acting on the body is :

A) 20 N                                      

B) 10 N

C) 5 N                                        

D) 15 N

Correct Answer: A

Solution :

Key Idea: An acceleration is always produced by a force that is directed towards its centre. A body performing circular motion is acted upon by a force which is always directed towards the centre of the circle. This force is called centripetal force. In the absence of this force circular motion is not possible. \[F=mass\times acceleration\] \[F=\frac{m{{v}^{2}}}{r}\] Also \[v=r\omega ,\]we have \[F=m{{\omega }^{2}}r\] Putting the numerical values from the question, we have \[\therefore \]     \[F=5\times {{(2)}^{2}}\times 1\]         \[F=20\,N\]