A `10kg` ball attached at the end of a rigid massless rod of length `1m` rotates at constant speed in a horizontal circle of radius `0.5m` and period of `1.58s` , as shown in the figure. The force exerted by the rod on the ball is `(g=10ms^(-2))`

Options

A. `158N`
B. `128N`
C. `110N`
D. `98N`

Answer

B

Explanation

`v=(22pir)/(T)=((2pi)(0.5))/(1.58)`

`~~2m//s`
`F_(1)=mg=100N`
`F_(2)=(mv^(2))/(r)=(10xx4)/(0.5)=80N`
:. Net force +by rod on ball
`=sqrt(F_(1)^(2)+F_(2)^(2))=128N`