A 14.3-g bullet is fired into a 5.21 kg block of wood. The block is attached to a spring that has a spring force constant of 450 N/m. The block and bullet continue to move, compressing the spring by 22.0 cm before the whole system momentarily comes to a stop. The coefficient of kinetic friction between block and the surface on which the block is resting is 0.35. Determine the initial speed of bullet.

The initial speed of the bullet is .

Explanation:

The collision between bullet and block is inelastic and let suppose that motion occurs on a horizontal surface, so that changes in gravitational potential energy can be neglected. Initially, the intial speed of the bullet-block system can be determined with the help of the Work-Energy Theorem and the Principle of Energy Conservation:

The initial speed of the bullet-block system is:

Now, the initial speed of the bullet is determined by applying the Principle of Momentum Conservation: