Two blocks, of mass 1 kg and 2 kg respectively, are connected by a spring and kept on a frictionless table. The blocks are pulled apart, so that the spring is stretched, and released from rest. At a certain instant of time, the block of mass 1 kg, is found to be moving at a speed 2 m / s. What must be the speed of the other block at this instant?

Question

Two blocks, of mass 1 kg and 2 kg respectively, are connected by a spring and kept on a frictionless table. The blocks are pulled apart, so that the spring is stretched, and released from rest. At a certain instant of time, the block of mass 1 kg, is found to be moving at a speed 2 m / s. What must be the speed of the other block at this instant? (A) 1 m/s (B) 0.5 m/s (C) 4 m/s (D) 0.25 m/s

Tardigrade Admin · Accepted Answer

According to conservation of linear momentum 0=m1 v1+m2 v2 0=1 × 2 × 2 × v2 v2=-1 m / s Negative sign shows that 2 kg is pulled in a opposite direction to that of mass 1 kg .

1 m/s

0.5 m/s

4 m/s

0.25 m/s

According to conservation of linear momentum 0=m1​v1​+m2​v2​ 0=1×2×2×v2 v2​=−1m/s Negative sign shows that 2kg is pulled in a opposite direction to that of mass 1kg .

According to conservation of linear momentum
$0 = m_{1} v_{1} + m_{2} v_{2}$
$0 = 1 \times 2 \times 2 \times v^{2}$
$v_{2} = - 1 m / s$
Negative sign shows that $2 k g$
is pulled in a opposite direction to that of mass $1 k g$ .