A body starts from rest and travels with a uniform acceleration of 20 m/s². Calculate the time taken by the body to cover a distance of 90 m.

CONCEPT:

• Equation of motion: The mathematical equations used to find the final velocity, displacements, time, etc of a moving object without considering force acting on it are called equations of motion.
• These equations are only valid when the acceleration of the body is constant and they move on a straight line.

There are three equations of motion:

V = u + at

V2 = u2 + 2 a S

Where, V = final velocity, u = initial velocity, s = distance traveled by the body under motion, a = acceleration of body under motion, and t = time taken by the body under motion.

CALCULATION:

Given that:

Acceleration (a) = 20 m/s²

Distance traveled (S) = 90 m

Initial Velocity (u) = 0

To find the time taken (t) to cover 90 m.

Equation of motion states that:

Time taken (t) = 3 sec

Hence option 2 is correct.