Question

A body of mass \(10\,\text{kg}\) is moving with a velocity of \(20\,\text{m/s}\). What is the kinetic energy?

• A. \(1000\,\text{J}\)
• B. \(2000\,\text{J}\)
• C. \(4000\,\text{J}\)
• D. \(500\,\text{J}\)

Hint:

Kinetic energy increases with the square of velocity. Doubling the velocity makes the kinetic energy four times larger.

Answer 1

The Correct Option is B

Concept: Kinetic energy is the energy possessed by a body due to its motion. It depends on the mass of the object and the square of its velocity. :contentReference[oaicite:0]{index=0} where
• \(m\) = mass of the body
• \(v\) = velocity of the body

Step 1: Substitute the given values. \[ m = 10\,\text{kg}, \quad v = 20\,\text{m/s} \] \[ K.E. = \frac{1}{2} \times 10 \times (20)^2 \]

Step 2: Perform the calculation. \[ K.E. = 5 \times 400 \] \[ K.E. = 2000\,\text{J} \] Thus, the kinetic energy of the body is: \[ K.E. = 2000\,\text{J} \]