Question

In each situation of column I, a uniform disc of mass $m$ and radius $R$ rolls on a rough fixed horizontal surface as shown. At $t=0$ (initially) the angular velocity of the disc is ${\omega }_0$ and velocity of the centre of mass of the disc is $v_0$ (in the horizontal direction). The relation between $v_0$ and ${\omega }_0$ for each situation and also the initial sense of rotation is given for each situation in column I. Then match the statements in column I with the corresponding results in column II.

Answer 1

For A: $V_o>R{\omega }_o$ (opposite)

So friction reduces V So friction is left K E is reduced as V is reduced For B: $V_o>R{\omega }_o$ (same) So friction stops both frictions is left KE is reduced For C: same as A For D: same as B