Question

- A body covers 12 m in second second and 24 m in fifth seconds. What is the distance covered in 11th second? ​

Answer 1

PLEASE REFER TO THE ABOVE ATTACHED IMAGE

Answer 2

Given: A body covers 12 m in 2nd second and 24 m in fifth second

To find: Distance covered in 11th second

Explanation: Let the initial velocity be u and acceleration be a.

Formula for calculating distance in nth second is:

S = u + a (2n-1)/2

In 2nd second, the body travels 12 m. Therefore, n= 2 and S = 12m.

12 = u + a(2*2-1) /2

=> 12 = u + 3a/2

=> 24 = 2u +3a...(i)

In 5th second, the body travels 24 m. Therefore, n= 5 and S = 24 m.

24 = u + a(2*5-1) /2

=> 24= u + 9a/2

=> 48 = 2u +9a...(ii)

Subtracting (i) from (ii),

24= 6a

=> a = 4

Putting a=4 in eqn. (ii)

48= 2u + 36

=> 2u = 12

=> u= 6

For n=11,

S = u+ a(2*11-1)/2

= 6 + 4*21/2

= 6+ 42

= 48 m

Therefore, distance covered in 11th second is 48 m.