05 Blocks A and C start from rest and move to the right
with acceleration a, = 12 tms' and a. =3 ms? Here
tis in seconds. The time when block Bagain comes to
rest is
(a) 2 s
(c) 3/2 s
(b) 13
(d) 1/2 s
Answers
Answer:
Explanation:
The block B will come to rest it means that the velocity of block B is zero.
The Blocks A,B,C are connected with the same rope.
By considering the portions of rope , we can see that the velocity of block B depends on Blocks A and C as...
velocity of block B (in downward)= (velocity of block A)/2 - (velocity of block C)/2
[By formula of constrained relation]
We are given accelerations. so velocity will be integration wrt time of acceleration.
so.......
Va = 6t^2 + c
Vc = 3t + c`
Here c and c` can be considered as initial velocity. these will be zero as blocks are at rest initially.
So.....
Vb= (Va - Vc)/2
Vb=(6t^2 - 3t)/2
Vb=0....
0 = (6t^2 -3t)/2
6t^2 -3t=0
t(6t-3)=0
t=0 or 6t-3=0
t=0 or t=1/2
Obviously Block is at rest at t=0 as given in question also ..XD
So at t=1/2sec block B will at rest