Question

A body moving with a velocity of 20 m/s begins to accelerate at 3 m/s2. How far does the body move in 5 seconds?

Answer 1

S = ut + 0.5at^2
S = 20*5 + 0.5*3*5^2
S = 100 + 75/2
S = 137.5m

It moves 137.5m in 5 seconds

Answer 2

The velocity of 20 m/s body moves and accelerates to 3 m/s^2 and moves 137.5 m in a 5 seconds duration.

Given:  

Velocity = 20 m/s = u

Acceleration = 3 m/s^2 = a

Time = 5 sec = t

Solution:

On using, equation of motion,

$s = ut + \frac{1}{2} at^2$

$s = (20 \ m/s \times 5 \ sec) + \frac{1}{2} (3 \ m/s^2) (5 \ sec)^2$

$s =100 \ m + (1.5 \ m/s^2) (25 \ s^2)$

$s = 100 \ m + 37.5 \ m$

$s = 137.5 \ meters$