Question

55. Blocks A and B are initially in equilibrium. The
springs and strings are ideal. The accelerations of
the blocks A and B, just after the spring-2 is cut,
are respectively
(1) g, 0
(2) g,g/2
(3) g, g
(4) O,g
plz genuine answer​

Answer 1

The accelerations of blocks A and B, just after the spring-2 is cut are g and 0 respectively. So, option 'A' is correct.

Given:-

Mass of Block A = m

Mass of Block B = 2m

To Find:-

The accelerations of the blocks A and B, just after the spring-2 is cut,

Solution:-

We can simply calculate the accelerations of

blocks A and B, just after the spring-2 is cut by using the following procedure.

As

Mass of Block A = m

Weight of A = mg

Tension in string A = T/2

Mass of Block B = 2m

Weight of B = 2mg

Tension in string B = T

Now when spring 2 is cut, block A falls freely and during free fall acceleration is always equal to g.

Therefore, a(A) = g

and mg = T/2

T = 2mg

But for Block B, the pseudo force acts on the system

W - T = 2ma(B)

2mg - 2mg = 2ma(B)

2ma(B) = 0

So, a(B) = 0

Hence, The accelerations of blocks A and B, just after the spring-2 is cut are g and 0 respectively. So, option 'A' is correct.

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