Question

A car starts from rest and moves with constant acceleration the ratio of distance covered in 3rd second to that covered in three second is​

Answer 1

5 : 18

Explanation:

Distance Covered in 3rd second will be the difference of (distance Covered in 3 seconds) and (distance Covered in 2 seconds).

So,

Distance Covered in 3 seconds =

s = ut + 1/2 at²

s = 0×t + 1/2 a 3² (Starts from rest u=0)

s = 9/2 a __(1)

and

Distance Covered in 2 seconds =

s = ut + 1/2 at²

s = 0×t + 1/2 a 2² (Starts from rest u=0)

s = 4/2 a = 2a __(2)

Now,

Distance Covered in 3rd second =

(1) - (2)

9/2 a - 2a

5/4 a __(3)

Ratio =

(3) : (1)

5/4 a : 9/2 a

5 : 18

Hope It Helps ;)