$A$ motor boat is travelling with a speed of $3.0 \, m/s$. If the force on it due to water flow is $500 \, N$,the power of the boat is:

The coefficient of $x^5$ in the expansion of $\left(2 x^3-\frac{1}{3 x^2}\right)^5$ is

$A$ proton enters a magnetic field of flux density $1.5 \, Wb/m^2$ with a velocity of $2 \times 10^7 \, m/s$ at an angle of $30^\circ$ with the field. The force on the proton will be

If $|\vec{A} \times \vec{B}| = \sqrt{3} \vec{A} \cdot \vec{B}$,then the value of $|\vec{A} + \vec{B}|$ is

Mass $M$ is divided into two parts $xM$ and $(1-x)M$. For a given separation,the value of $x$ for which the gravitational attraction between the two pieces becomes maximum is

The coefficient of performance of a refrigerator is $5$. If the temperature inside the freezer is $-20\,^{\circ}C$,the temperature of the surroundings to which it rejects heat is ....... $^{\circ}C$.