Question

A bullet of mass 30 g has its kinetic energy equal to 54 J. Find the speed of the bullet.

Answer 1

See the attached photo.

Hope it helps..!!

Answer 2

Provided that:

• Mass of bullet = 30 g
• Kinetic energy = 54 J

To calculate:

• Speed of bullet

Solution:

• Speed of bullet = 60 mps

Using concepts:

• Kinetic energy formula
• Formula to convert g into kg

Using formulas:

• KE = ½mv²
• 1 g = 1/1000 kg

Where, KE denotes kinetic energy, m denotes mass and v denotes velocity.

Required solution:

✡️ Firstly let us convert g into kg by using the formula to convert gram into kilograms!

»»» 1 g = 1/1000 kg

»»» 30 g = 30/1000 kg

»»» 30 g = 3/100 kg

»»» 30 g = 0.03 kg

• Henceforth, converted!

✡️ Now let us find out the speed of bullet by using kinetic energy formula!

»»» KE = ½mv²

»»» 54 = ½ × 0.03 × v²

»»» 54 = 0.03/2 × v²

»»» 54 = 3/200 × v²

»»» 54 × 200 = 3 × v²

»»» 10800 = 3 × v²

»»» 10800/3 = v²

»»» 3600 = v²

»»» √3600 = v

»»» v = 60 mps

»»» Speed of bullet = 60 mps $\:$