Question

(d) A pump is used to lift 100 kilogram of water from a well 30 metre deep in 20 seconds
Find work done by the pump and power spent by the pump. (Take ge 10ms)​

Answer 1

Answer :

Mass of water = 100kg

Depth of well = 30m

Time interval = 20s

We have to find work done by the pump and power spent by the pump$.$

★ Work done is measured as the product of force and displacement. W = F s

• It is a scalar quantity.
• SI unit : J

Here force acts on water is only gravitational force which is equal to mg.

➝ W = F d

➝ W = m g d

➝ W = 100 × 10 × 30

➝ W = 30,000 J = 30 kJ

★ Power is defined as the work done per unit time. P = W/t

• It is also a scalar quantity.
• SI unit : J/s or W (watt)

➝ P = W/t

➝ P = 30,000/20

➝ P = 1500 W = 1.5 kW