The ratio of the moments of inertia of two spheres, about their diameters, having the same mass and their radii being in the ratio of \(1:2\), is:
1. | \(2:1\) | 2. | \(4:1\) |
3. | \(1:2\) | 4. | \(1:4\) |
A string is wrapped along the rim of a wheel of the moment of inertia \(0.10~\text{kg-m}^2\) and radius \(10~\text{cm}.\) If the string is now pulled by a force of \(10~\text N,\) then the wheel starts to rotate about its axis from rest. The angular velocity of the wheel after \(2~\text s\) will be:
1. | \(40~\text{rad/s}\) | 2. | \(80~\text{rad/s}\) |
3. | \(10~\text{rad/s}\) | 4. | \(20~\text{rad/s}\) |
Assertion (A): | For a body under translatory as well as rotational equilibrium, net torque about any axis is zero. |
Reason (R): | \( \Sigma \vec{F}_{i}=0 \text { and } \Sigma\left(\vec{r}_{i} \times \vec{F}_{i}\right)=0 \) implies that \( \Sigma\left(\vec{r}_{i}-\overrightarrow{r_{0}}\right) \times \vec{F}=0 \). | Together
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
Assertion (A): | The axis of rotation of a rigid body cannot lie outside the body. |
Reason (R): | It must pass through a material particle of the body. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
The ratio of the radius of gyration of a circular disc to that of a circular ring, both having the same mass and radius, about their respective axes is:
1. | \(\sqrt2:\sqrt3\) | 2. | \(\sqrt3:\sqrt2\) |
3. | \(1:\sqrt2\) | 4. | \(\sqrt2:1\) |
1. | \(-\frac{\pi}{100} ~\text{N-m}\) | 2. | \(-\frac{\pi}{50} ~\text{N-m}\) |
3. | \(-\frac{\pi}{20} ~\text{N-m}\) | 4. | \(-\frac{\pi}{10}~\text{N-m}\) |
1. | \(0.7~\text{kg-m}^2\) | 2. | \(3.22~\text{kg-m}^2\) |
3. | \(30.8~\text{kg-m}^2\) | 4. | \(0.07~\text{kg-m}^2\) |