62
Lokesh Verma
·2009-03-04 05:52:01
1/2 g. t2 = 2.4
t2 = 4.8g
v= √4.8 t
downward, displacemnt will be 35 m for the ball..
-35= √4.8 tt - 1/2 g t2
now solve for t
there iwll be one -ve root. ignore that :)
11
virang1 Jhaveri
·2009-03-04 06:03:25
Bhaiyya the displacement is not 2.4 it is 30m of the elevator with the ball intact to the ceiling. 2.4 is the acceleration of the elevator and after 30 m the string holding the ball breaks and the ball falls . The time according to me is 0.67seconds
Please tell me if i am wrong
3
iitimcomin
·2009-03-04 06:08:30
lets luk at i frm outside point of view ..........
√2(2.4)30 = v =initial vel. upwards ..........
1/2gt2 - vt = 5 - distance covered by base of elevater in dat time.......
11
virang1 Jhaveri
·2009-03-04 06:12:05
No iitimcoming it is wrong pls read the question again
11
virang1 Jhaveri
·2009-03-04 06:13:25
You forgot that when the string breaks the ball has a upward velocity which has to be considered.
3
iitimcomin
·2009-03-04 06:13:47
ive concidered it ,,, luk at mah soln.
11
virang1 Jhaveri
·2009-03-04 06:16:48
I think that you have not considered the acceleration of the elevator and its velocity.
3
iitimcomin
·2009-03-04 06:18:36
""""""""""""lets luk at i frm outside point of view """""""""
is a key statement ... so i havnt included psudo force bhai.....
u can do it other way also...
3
iitimcomin
·2009-03-04 06:19:12
""""""distance covered by base of elevater in dat time"""""""""""
covers all that ....
11
virang1 Jhaveri
·2009-03-04 06:24:50
ok i got it I did not read "distance covered by the base of the elevator"
You r rite.
11
mona100
·2009-03-07 03:15:15
wats the correct answer???????
i am getting 1.15 sec.
11
virang1 Jhaveri
·2009-03-13 22:15:25
Yes Mona your answer is rite.
21
tapanmast Vora
·2009-03-14 02:21:33
can sum1 cont. n complete the solutn by IITijmcumin...