Question

A body falls from rest.It covers as much distance in the last second of its motion as covered d in the first 3 seconds.The body has fallen for a time of___

Answer 1

Is it 3 seconds?

Answer 2

@Yahoo!

Answer 3

Do u knw the formula for the dist travelled in nth second

Answer 4

Yes

Answer 5

can u write that

Answer 6

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

Answer 7

u certainly misses out "a"

Answer 8

sorry yeah..

Answer 9

just confirm my answer :(

Answer 10

wat is ur answer

Answer 11

3?

Answer 12

i dont think it is 3

Answer 13

@experimentX @mukushla @ajprincess

Answer 14

s1 = 1/2 * a * t^2

Answer 15

= 5 * 9 = 45 m

Answer 16

dn = u + a/2 [ 2n-1]

Answer 17

45 = 5 * { 2n -1)

9 = 2n -1

n = 5

Answer 18

so..5 seconds

Answer 19

shouldn't it be
2(n-1-1) ? how do we know nth second means last second here?

Answer 20

did nt understand ur question lol

Answer 21

Formula for the distance travelled in n th second where n = 1 ,2 , 3....................................dn = u + a/2 [ 2n-1]

Answer 22

nop @ajprincess dn = u + a/2 [ 2n-1] = dn = u + a [ n-1/2]

Answer 23

ya u right.@yahoo!. Sorry abt the interruption. carry on.

Answer 24

no problem

Answer 25

what according to u is n in 2n-1 ?

Answer 26

n === time

Answer 27

n means nth second.............

Answer 28

yup.....

Answer 29

but here we are asked n-1 second so..
shouldn't it be
2n-1-1?

Answer 30

so...5 th second is last second

Answer 31

im confused nvm :/

Answer 32

just read the question

Answer 33

It covers as much distance in the last second of its motion as covered d in the first 3 seconds

Answer 34

thanks

Answer 35

"last second of its motion"

Answer 36

u understood??