Question

If a body of mass 5 kg has a linear momentum of 4 kg⋅m/s, find the kinetic energy.

• A. 4J
• B. 8J
• C. 16J
• D. 32J

Hint:

The kinetic energy of a body is given by \( K.E. = \frac{p^2}{2m} \), where \( p \) is the linear momentum and \( m \) is the mass of the body.

Answer 1

The Correct Option is B

Step 1: Use the formula for kinetic energy.
The kinetic energy (\( K.E. \)) is related to the linear momentum (\( p \)) and mass (\( m \)) by the formula: \[ K.E. = \frac{p^2}{2m} \] Where:
- \( p = 4 \, \text{kg⋅m/s} \),
- \( m = 5 \, \text{kg} \).

Step 2: Substitute the given values.
Substitute \( p = 4 \, \text{kg⋅m/s} \) and \( m = 5 \, \text{kg} \): \[ K.E. = \frac{(4)^2}{2 \times 5} = \frac{16}{10} = 8 \, \text{J} \]
Final Answer: 8J.