Water falls on the blades of a turbine at a rate of $100 \ kg/s$ from a height of $100 \ m$. The power generated is . . . . . . $kW$.

An engine develops $10 \text{ kW}$ of power. How much time will it take to lift a mass of $200 \text{ kg}$ to a height of $40 \text{ m}$? $(g = 10 \text{ m/s}^2)$

An electric motor produces a tension of $4500 N$ in a wire and the reel winds at a rate of $2 ms^{-1}$. What is the power of the electric motor?

Assume the aerodynamic drag force on a car is proportional to its speed. If the power output from the engine is doubled,then the maximum speed of the car:

$1\,kWh$ is a unit of power. This statement is true or false? If it is wrong,then correct it.

An elevator can carry a maximum load of $1800 \; kg$ (elevator $+$ passengers) and is moving up with a constant speed of $2 \; m s^{-1}$. The frictional force opposing the motion is $4000 \; N$. Determine the minimum power delivered by the motor to the elevator in watts as well as in horsepower.