**Question**

**A moving body of mass 10 kg has 20 Joules of kinetic energy. Calculate the speed of the body. [Ans. 2 m/s] **

**Answer**

Mass (m) = 10 kg

Kinetic Energy (KE) = 20 J

Speed (v) = To be calculated

Kinetic Energy (KE) = {1\over2}×m×v^2

or, {1\over2}×10×v^2 = 20

or, v^{2} = 20 × 2\over 10

or, speed (v) = √4 = 2 m/s