A car of mass 1000 kg moves on a circular track with a radius of 40 m. If the coefficient of friction is 1.28, the maximum velocity with which the car can be moved is:
1. \(22.4~\text{m/s}\)
2. \(112~\text{m/s}\)
3. \(\frac{0.64\times40}{1000\times100}~\text{m/s}\)
4. \(1000~\text{m/s}\)
Light travels faster in the air than in glass. This is in accordance with:
1. | the wave theory of light. |
2. | the corpuscular theory of light. |
3. | neither (1) nor (2) |
4. | both (1) and (2) |
The speed of airflow on the upper and lower surfaces of a wing of an aeroplane is \(v_1\) and \(v_2\) respectively. If \(A\) is the cross-section area of the wing and \(\rho\) is the density of air, then the upward lift is:
1. \(\frac12\rho A(v_2-v_2)\)
2. \(\frac12\rho A(v_1+v_2)\)
3. \(\frac12\rho A(v_1~^2-v_2~^2)\)
4. \(\frac12\rho Av_1~^2+v_2~^2\)
The work done in increasing the size of a soap film for \(10~ \mathrm{cm} \times 6~ \mathrm{m}\) to \(10~ \mathrm{cm} \times 11~ \mathrm{m}\) is \(3\times 10^{-4}\) J. The surface tension of the film is:
1. \(1.0 \times10^{-2}\) N/m
2. \(6.0 \times 10^{-2}\) N/m
3. \(3.0 \times 10^{-2}\) N/m
4. \(1.5 \times 10^{-2}\) N/m
A parallel plate condenser is filled with two dielectrics as shown in the figure. The area of each plate is \(A~\text m^2\) and the separation is \(d\) meter. The dielectric constants are \(K_1\) and \(K_2\) respectively. Its capacitance in farad will be:
1. \(\frac{2\varepsilon_{_0}A}{d}\Big(\frac{K_1+K_2}{K_1K_2}\Big)\)
2. \(\frac{2\varepsilon_{_0}A}{d}\Big(\frac{K_1K_2}{K_1+K_2}\Big)\)
3. \(\frac{\varepsilon_{_0}A}{d}\Big(\frac{K_1+K_2}{2K_1K_2}\Big)\)
4. \(\frac{\varepsilon_{_0}AK_1K_2}{2(d_2K_1+d_1K_2)}\)