269410
A metallic circular plate is rotating about its axis without friction. If the radius of plate expands by\(0.1 \%\) then the \% change in its moment of inertia is
1 increase by\(0.1 \%\)
2 decrease by\(0.1 \%\)
3 increase by\(0.2 \%\)
4 decrease by\(0.2 \%\)
Explanation:
\(I \propto R^{2}\) and \(\frac{\Delta I}{I}=2 \frac{\Delta R}{R}\)
Rotational Motion
269411
A constant torque acting on a uniform circular wheel changes its angular momentum from \(A\) to \(4 \mathrm{~A}\) in \(4 \mathrm{sec}\). The torque acted on it is
1 \(\frac{3 A}{4}\)
2 \(\frac{A}{4}\)
3 \(\frac{2 A}{4}\)
4 \(\frac{3 A}{2}\)
Explanation:
\(\tau=\frac{L_{2}-L_{1}}{t}\)
Rotational Motion
269412
Density remaining constant, if earth contracts to half of its present radius, duration of the day would be (in minutes)
1 45
2 80
3 100
4 120
Explanation:
\(I_{1} \omega_{1}=I_{2} \omega_{2}\) and \(R_{1}{ }^{5} T_{1}=R_{2}{ }^{5} T_{2}\)
Rotational Motion
269413
A mass is whirled in a circular path with an angular momentum\(L\). If the length of string and angular velocity, both are doubled, the new angular momentum is
1 \(\mathrm{L}\)
2 \(4 \mathrm{~L}\)
3 \(8 \mathrm{~L}\)
4 \(16 \mathrm{~L}\)
Explanation:
\(L=m r \omega^{2} ; L \propto r \omega^{2} ; \frac{L_{1}}{L_{2}}=\frac{r_{1}}{r_{2}} \times\left[\frac{\square \omega_{1}}{\omega_{2}}\right.\) \(^{2}\)
269410
A metallic circular plate is rotating about its axis without friction. If the radius of plate expands by\(0.1 \%\) then the \% change in its moment of inertia is
1 increase by\(0.1 \%\)
2 decrease by\(0.1 \%\)
3 increase by\(0.2 \%\)
4 decrease by\(0.2 \%\)
Explanation:
\(I \propto R^{2}\) and \(\frac{\Delta I}{I}=2 \frac{\Delta R}{R}\)
Rotational Motion
269411
A constant torque acting on a uniform circular wheel changes its angular momentum from \(A\) to \(4 \mathrm{~A}\) in \(4 \mathrm{sec}\). The torque acted on it is
1 \(\frac{3 A}{4}\)
2 \(\frac{A}{4}\)
3 \(\frac{2 A}{4}\)
4 \(\frac{3 A}{2}\)
Explanation:
\(\tau=\frac{L_{2}-L_{1}}{t}\)
Rotational Motion
269412
Density remaining constant, if earth contracts to half of its present radius, duration of the day would be (in minutes)
1 45
2 80
3 100
4 120
Explanation:
\(I_{1} \omega_{1}=I_{2} \omega_{2}\) and \(R_{1}{ }^{5} T_{1}=R_{2}{ }^{5} T_{2}\)
Rotational Motion
269413
A mass is whirled in a circular path with an angular momentum\(L\). If the length of string and angular velocity, both are doubled, the new angular momentum is
1 \(\mathrm{L}\)
2 \(4 \mathrm{~L}\)
3 \(8 \mathrm{~L}\)
4 \(16 \mathrm{~L}\)
Explanation:
\(L=m r \omega^{2} ; L \propto r \omega^{2} ; \frac{L_{1}}{L_{2}}=\frac{r_{1}}{r_{2}} \times\left[\frac{\square \omega_{1}}{\omega_{2}}\right.\) \(^{2}\)
269410
A metallic circular plate is rotating about its axis without friction. If the radius of plate expands by\(0.1 \%\) then the \% change in its moment of inertia is
1 increase by\(0.1 \%\)
2 decrease by\(0.1 \%\)
3 increase by\(0.2 \%\)
4 decrease by\(0.2 \%\)
Explanation:
\(I \propto R^{2}\) and \(\frac{\Delta I}{I}=2 \frac{\Delta R}{R}\)
Rotational Motion
269411
A constant torque acting on a uniform circular wheel changes its angular momentum from \(A\) to \(4 \mathrm{~A}\) in \(4 \mathrm{sec}\). The torque acted on it is
1 \(\frac{3 A}{4}\)
2 \(\frac{A}{4}\)
3 \(\frac{2 A}{4}\)
4 \(\frac{3 A}{2}\)
Explanation:
\(\tau=\frac{L_{2}-L_{1}}{t}\)
Rotational Motion
269412
Density remaining constant, if earth contracts to half of its present radius, duration of the day would be (in minutes)
1 45
2 80
3 100
4 120
Explanation:
\(I_{1} \omega_{1}=I_{2} \omega_{2}\) and \(R_{1}{ }^{5} T_{1}=R_{2}{ }^{5} T_{2}\)
Rotational Motion
269413
A mass is whirled in a circular path with an angular momentum\(L\). If the length of string and angular velocity, both are doubled, the new angular momentum is
1 \(\mathrm{L}\)
2 \(4 \mathrm{~L}\)
3 \(8 \mathrm{~L}\)
4 \(16 \mathrm{~L}\)
Explanation:
\(L=m r \omega^{2} ; L \propto r \omega^{2} ; \frac{L_{1}}{L_{2}}=\frac{r_{1}}{r_{2}} \times\left[\frac{\square \omega_{1}}{\omega_{2}}\right.\) \(^{2}\)
269410
A metallic circular plate is rotating about its axis without friction. If the radius of plate expands by\(0.1 \%\) then the \% change in its moment of inertia is
1 increase by\(0.1 \%\)
2 decrease by\(0.1 \%\)
3 increase by\(0.2 \%\)
4 decrease by\(0.2 \%\)
Explanation:
\(I \propto R^{2}\) and \(\frac{\Delta I}{I}=2 \frac{\Delta R}{R}\)
Rotational Motion
269411
A constant torque acting on a uniform circular wheel changes its angular momentum from \(A\) to \(4 \mathrm{~A}\) in \(4 \mathrm{sec}\). The torque acted on it is
1 \(\frac{3 A}{4}\)
2 \(\frac{A}{4}\)
3 \(\frac{2 A}{4}\)
4 \(\frac{3 A}{2}\)
Explanation:
\(\tau=\frac{L_{2}-L_{1}}{t}\)
Rotational Motion
269412
Density remaining constant, if earth contracts to half of its present radius, duration of the day would be (in minutes)
1 45
2 80
3 100
4 120
Explanation:
\(I_{1} \omega_{1}=I_{2} \omega_{2}\) and \(R_{1}{ }^{5} T_{1}=R_{2}{ }^{5} T_{2}\)
Rotational Motion
269413
A mass is whirled in a circular path with an angular momentum\(L\). If the length of string and angular velocity, both are doubled, the new angular momentum is
1 \(\mathrm{L}\)
2 \(4 \mathrm{~L}\)
3 \(8 \mathrm{~L}\)
4 \(16 \mathrm{~L}\)
Explanation:
\(L=m r \omega^{2} ; L \propto r \omega^{2} ; \frac{L_{1}}{L_{2}}=\frac{r_{1}}{r_{2}} \times\left[\frac{\square \omega_{1}}{\omega_{2}}\right.\) \(^{2}\)
