$A$ man does a given amount of work in $10 \ s$. Another man does the same amount of work in $20 \ s$. The ratio of the output power of the first man to the second man is:

$A$ body of mass '$M$' is moving with a uniform speed of '$v$' on a frictionless horizontal surface under the influence of two forces $F_1$ and $F_2$ as shown in the figure. The net power of the system is

Water falls from a dam at a height of $550 \ m$ onto a turbine at a height of $50 \ m$ at a rate of $2000 \ kg$ per second. If the efficiency of the turbine is $80\%$,the power generated is ............. $MW$.

$A$ motor can pump $7560 \text{ kg}$ of water per hour from a well of depth $100 \text{ m}$. If the efficiency of the pump is $70 \%$, then the power of the pump is (Acceleration due to gravity $= 10 \text{ m s}^{-2}$) (in $\text{ kW}$)

$A$ force of $5 \,N$ acts on a body initially at rest. If the instantaneous power due to the force at the end of the third second $(t=3 \,s)$ is $5 \,W$, then the mass of the body is (in $\,kg$)

An electric motor exerts a force of $50 \,N$ on a cable and pulls it through $60 \,m$ in $1 \,min$. The power supplied by the motor is (in $\,W$)