Question

If the radius of a circular path of a body revolving at a constant speed is doubled, the value of the centripetal forece will be

• A. halved
• B. doubled
• C. four time
• D. unchanged

Answer 1

Answer: (A)

halved

Centripetal force $F=\frac{m{v}^2}{r}$

Now the radius is doubled keeping the speed constant i.e $v^{\prime }=v$ and $r^{\prime }=2r$

$\therefore$ New centripetal acceleration $F^{\prime }=\frac{m{v}^2}{2r}=\frac{F}{2}$

Thus the value of centripetal force is halved.