A 12.0-g bullet fired horizontally into a 100-g wooden block that is initially at rest on frictionless horizontal surface and connected to a spring having spring constant 150 N/m. The bullet becomes embedded in the block. If the bullet-block system compresses the spring by a maximum of 80.0 cm, what was the speed of the bullet at impact with the block?(273 m/s)

Respuesta :

Explanation:

As the given collision is inelastic in nature. Therefore, momentum will be conserved. Also, both the block and bullet have the same final velocity.

Therefore, formula will be as follows.

        [tex]m_{1}v_{1} + m_{2}v_{2} = V_{f}(m_{1} + m_{2})[/tex]

Also,

       [tex]\frac{1}{2}kx^{2} = \frac{1}{2}V^{2}_{f}(m_{1} + m_{2})[/tex]

where,  k = spring constant

            x = compression of spring

         [tex]m_{1}[/tex] = mass of bullet

         [tex]m_{2}[/tex] = mass of wooden block

Putting the given values into the above formula as follows.

        [tex]\frac{1}{2}kx^{2} = \frac{1}{2}V_{f}^{2}(m_{1} + m_{2})[/tex]

        [tex]\frac{1}{2}150 N/m \times (0.8 m)^{2} = \frac{1}{2}V^{2}_{f}(12 g + 100 g)[/tex]

                [tex]V_{f}[/tex] = 273.2 m/s

                            = 273 m/s (approx)

Therefore, we can conclude that speed of the bullet is coming with 273 m/s at impact with the block.