Question

An object starts moving from rest on a straight line path with uniform acceleration and covers a distance of 100 m in first 10 s. The distance it covers in next 5 s is

Answer 1

Distance = 100m
Time = 10s
Therefore speed = d/t = 100/10 = 10 m/s

So distance covered in 5 s = s*t = 10*5 = 50m

Is it correct?

Answer 2

Given that the object starts moving from rest, so. its initial velocity will be zero.
Hence, Vi = o
The object covers a distance = S = 100 m in time t = 10 sec
We have to calculate the distance "d" covered in time t = 5 sec
Here we use Newton Equation of motion:
S = Vi . t + 1/s a . t² ........... (1)
First we have to calculate the value of "a"
For this, substituting the given values in equation (1), we get: 
100 = (0) . (10) + 1/2 (a) . (10)²
100 = 1/2 (a) . (100)
a = 2 m/s²
Now put this value of "a" again in equation (1) with time t = 5 sec
S = (0) . (5) + 1/2 (2) . (5)²
S = 25 m/s
Hence the distance covered by the object in next 5 seconds will be 25 m/s