MHT CET 2025 22nd April Morning Shift | Rotational Motion Question 1 | Physics

A solid sphere of mass ' $m$ ' and radius ' $R$ ' is rotating about its diameter. A solid cylinder of the same mass and same radius is also rotating about its geometrical axis with angular speed twice that of sphere. The ratio of kinetic energy of sphere to kinetic energy of cylinder will be

$2: 3$

$1: 5$

$3: 1$

$1: 4$

MHT CET 2025 22nd April Morning Shift

MCQ (Single Correct Answer)

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A solid sphere and thin walled hollow sphere have same mass and same material. Which of them have greater moment of inertia about their diameter?

[ $\mathrm{I}_{\mathrm{h}}=$ moment of inertia of hollow sphere about an axis coinciding with its diameter, $\mathrm{I}_5=$ moment of inertia of solid sphere about an axis coinciding with its diameter]

$\mathrm{I}_{\mathrm{s}}>\mathrm{I}_{\mathrm{h}}$

$\quad I_h \geqslant I_s$

$\mathrm{I}_{\mathrm{h}}>\mathrm{I}_{\mathrm{s}}$

$I_h=I_s$

MHT CET 2025 22nd April Morning Shift

MCQ (Single Correct Answer)

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If force $\vec{F}=-3 \hat{i}+\hat{j}+5 \hat{k}$ acts along $\vec{r}=7 \hat{i}+3 \hat{j}+\hat{k}$ then the torque acting at that point is

$(14 \hat{\mathrm{i}}-38 \hat{\mathrm{j}}+16 \hat{\mathrm{k}})$

$(-14 \hat{i}+34 \hat{j}-16 \hat{k})$

$(21 \hat{\mathrm{i}}+4 \hat{\mathrm{j}}+4 \hat{\mathrm{k}})$

$(4 \hat{\mathrm{i}}+4 \hat{\mathrm{j}}+6 \hat{\mathrm{k}})$

MHT CET 2025 21st April Evening Shift

MCQ (Single Correct Answer)

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The moment of inertia of a ring about an axis passing through its centre and perpendicular to its plane is I. It is rotating with angular velocity $\omega$. Another identical ring is gently placed on it so that their centres coincide. If both the rings are rotating about the same axis then loss in kinetic energy is

$\frac{\mathrm{I} \omega^2}{16}$

$\frac{\mathrm{I} \omega^2}{8}$

$\frac{\mathrm{I} \omega^2}{4}$

$\frac{\mathrm{I} \omega^2}{2}$

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