Question

If the blocks A and B are moving towards each other with acceleration a and b respectively (with ground) as shown in Fig. The net acceleration of block C with respect to ground. Assume all surfaces to be smooth.

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

Acceleration of C in horizontal direction = acceleration of A = a (right direction) = $a\hat{i}$
Acceleration of C in vertical downward direction = $-2(a+b)\hat{j}$
Hence, net acceleration of $C=a\hat{i}-2(a+b)\hat{j}$ (see figure)

From length constraint
$l_1+l_2+l_3+l_4=C$
$l{"}_1+l{"}_2+l{"}_3+l{"}_4=0$
-a - b + 0 - a - b + c = 0
c = 2a + 2b
From wedge constrains, acceleration of C towards right side is a.
Acceleration of C with respect to ground = $a\hat{i}-2(a+b)\hat{j}$