If a body having initial velocity zero is moving with uniform acceleration 8 m / sec², the distance travelled by it in fifth second will be

The correct option is 36 metres.

To find the distance travelled by a body in a specific second (the n-th second) under uniform acceleration, we use the following equation of motion:

$S_n=u+\frac{a}{2}(2n-1)$

Where:
• $u$ is the initial velocity of the body.
• $a$ is the uniform acceleration.
• $n$ is the specific second of motion.

From the problem, we are given the following values:
• Initial velocity, $u=0\text{m/s}$ (since the body starts from rest)
• Acceleration, $a=8{\text{m/s}}^2$
• Time interval, $n=5$ (fifth second)

Substituting these values into the formula:

$S_5=0+\frac{8}{2}\left(2\right(5)-1)$

Now, simplify the terms inside the expression step-by-step:

$S_5=4(10-1)$

$S_5=4\left(9\right)$

$S_5=36\text{metres}$

Thus, the distance travelled by the body in the fifth second is 36 metres.