Consider a block of mass 15 Kg that follows a circular motion. Its mass decreases at the rate of 0.3 Kg/s. At what time will the centripetal force be zero on the block ?
Answer & explanation
Correct answer: option 3
Centripetal force $ \propto $ m
As $m \rightarrow 0$ , $\text{Centripetal force } \rightarrow 0$
m = 18 - 0.3t
m = 0 = 18 - 0.3 t
$\Rightarrow t = \frac{18}{0.3} = 60 s$