Question

an object starts from rest and attains an uniform acceleration of 4m/s2.It's velocity at the end of half meter is?

Answer 1

Given Data:
Initial velocity = Vi = 0 m/s  ( Because object starts its motion from rest)
Acceleration = 4 m/s²
 Distance = 0.5 m
Final velocity = Vf = ?
Solution:
Using 3rd Equation of Motion, 
2aS = Vf² - Vi²
Vf² = 2aS + Vi²
Vf² = 2 (4) (0.5) + (0)²
Vf² = 4 
Vf = √ 4
Vf = 2 m/s²
Hence, the velocity at t he end of half meter is 2 m/s² 
Hope it will help you.
Thanks.

Answer 2

Given:
Initial velocity= 0m/s
Acceleration = 4m/s2
Final velocity =?
Distance = s=0.5 m
From third equation of motion
V^2 - u^2=2as
V2= 2x0.5x4
=2×5×4/10
=4m/s
V=2m/s

Therefore final velocity= 2m/s