# A 3-kg book is tossed across the room at a speed of 5 m/s. What is the kinetic energy of the...

## Question:

A 3-kg book is tossed across the room at a speed of 5 m/s. What is the kinetic energy of the book?

A. 0.75 J

B. 3.75J

C. 15 J

D. 75 J

## Kinetic Energy:

Mechanical energy is composed of two parts: it's a sum of kinetic energy and potential energy. The kinetic energy of a body is half the product of the mass of the body and the square of the velocity of the body. The S.I unit of energy is the Joule, J.

The kinetic energy, {eq}K.E {/eq}, of the book of mass, {eq}m = 3\ \rm{kg} {/eq}, moving at a speed, {eq}v = 5\ \rm{m/s} {/eq} is given by,

{eq}\begin{align*} K.E &= \frac{1}{2}mv^2\\ &= \frac{1}{2} \times 3 \times 5^2\\ &= 37.5\ \rm{J} \end{align*} {/eq}

None of the given solutions agrees with the correct answer.