question_answer

As shown in figure, S is a point on a uniform disc rolling with uniform angular velocity on a fixed rough horizontal surface. The only forces acting on the disc are its weight and contact forces exerted by horizontal surface. Which graph best represents the magnitude of the acceleration of point S as a function of time

A)

B)

C)

D)

Correct Answer: C

Solution :

Since angular velocity is constant, acceleration of centre of mass of disc is zero. Hence the magnitude of acceleration of point S is \[{{\omega }^{2}}x\] where \[\omega \] is angular speed of disc and x is the distance of S from centre. Therefore the graph is