Question

The speed of a bullet of mass 20g is 216kmh-1 what is its K.E. in joules?

Answer 1

Answer

• Kinetic Energy , KE = 36 Joules

Given

• The speed of a bullet of mass 20 g is 216 km/h

To Find

• Kinetic Energy in Joules

Solution

We know that ,

1 Joules = 1 N-m = 1 kg-m²/s²

Here ,

Mass of the bullet , m = 20 g = 0.02 kg

Speed of the bullet , v = 216 km/h = 216 × (5/18) = 60 m/s

Now ,

Kinetic Energy , KE = ¹/₂ mv²

⇒ KE = ¹/₂ × 0.02 × ( 60² )

⇒ KE = 0.02 × 30 × 60

⇒ KE = 36 Joules