**P.No.****4.6****:- 100m³ of water is pumped from a reservoir into a tank, 10m higher than the reservoir, in 20 minutes. Find**

**(a)**

**The increase in P.E**

**(b)**

**The power delivered by the pump.**

**Solution****:-**

**Given data****:-**

**Volume of water**

**= V =**

**100m³**

**Height**

**= h =**

**10m**

**Time taken**

**= t =**

**20min**

**=**

**20 × 60s**

**= 1200s**

**To determine****:-**

**Potential energy =**

**P.E =?**

**Power**

**=**

**P**

**=?**

**Calculation****:-**

**( we know that work done is equal to change in energy it may be kinetic or potential but**

**in this case only P.E is involved. So,)**

**Work done = Increase in P.E**

**= mgh**

**To determine mass ‘m’ we first take**

**Density = mass/volume**

**Or,**

**ρ = m/V**