Question

Two blocks of masses 8 kg and 4.3 kg are placed on a horizontal, frictionless surface. A light spring is attached to one of them, and the blocks are pushed together with the spring between them. A cord holding them together is burned, after which the block of mass 4.3 kg moves to the right with a speed of 6.7 m/s. What is the velocity of other mass in m/s?

Answer 1

Answer:

The velocity of other mass is 3.60 m/s.

Explanation:

Given that,

Mass of first block = 8 kg

mass of second block = 4.3 kg

Speed = 6.7 m/s

We need to calculate the speed of first mass

Using conservation of momentum

$(m_{1}+m_{2})u=m_{1}v_{1}+m_{2}v_{2}$

where, m₁ =mass of first block

m₂ =mass of second block

m₁ =mass of first block

v₂ =speed of second block

Put the value into the formula

$8+4.3\times0=8\times v_{1}+4.3\times6.7$

$v_{1}=\dfrac{-4.3\times6.7}{8}$

$v_{1}=-3.60\ m/s$

Negative sign represent the opposite direction of initial value.

Hence, The velocity of other mass is 3.60 m/s.