Question

A body is moving towards north with initial velocity of 13m/s. Its is subjected to a retardation of 2 m/s2 towards south.The distance travelled in 7th sec is ??

Joshi sir comment

displacement of any particular sec. = u+at-(a/2)

here direction of motion is opposite to the direction of acceleration so formula will be u-at+(a/2) 

displacement in 7th sec = 0

now we know that direction of motion will become south after 6.5 sec. so distance for last half sec = ut+(1/2)at= 1/4

same will be the distance for the first half sec of 7th. so total distance for 7th sec = 1/4 + 1/4 = 1/2

 

Read 3 Solution.

using sn = u+a/2(2n-1)

sn is the distance travelled in nth second u=initial vel a=accn
we get s7=0
hence the ans=0

IITMAX 10 year ago is this solution helpfull: 5 23

but the answer is not 0 m.

NIKHIL VARSHNEY 10 year ago is this solution helpfull: 4 14

42

SAHIL KUMAR 10 year ago is this solution helpfull: 1 13

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