Question

a motor is used to lift water from a well of depth 10m and to fill a water tank of volume 30 m^3 in 10 minutes . the tank is at height of 20 m above ground. if 20% of energy is wasted the power of the motor is?

Answer 1

The power of motor is 18000 watt.

Explanation:

We know that;

• work =$mass \times g \times height$

• work = mgh

Since, the depth of well is 10 miter. and tank's height is 20 miter above the ground.

• For the motor, we add both these heights.

• Height = 10 + 20 =30 miter.

• volume of the water tank =$30 m^3$

We know the density of water is $10^3 kg/ m^3.$

• Now, we can find out the mass of water by using the formula [ mass = $volume \times density$]

• mass of water = $30 \times 10^3$ = 30000 kg

Now, work done =$mass \times g \times height$

  W = $30000 \times 10 \times 30 = 9000000 \ joule$

We know that;

• power = $\dfrac{work \ done}{time}$

Time is given as 10 minutes or 600 sec.

power =$\dfrac{9000000}{600}$

power = 15000 watt

But, motor waste its 20% energy.

• It means that the original power of motor = 15000 + 20% of 15000

        = 15000 + 3000 = 18000 watt

Thus, the power of motor is 18000 watt.

Answer 2

Answer:

,

Explanation:

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