A block of wood (M_block = 7.9 kg) rests on a horizontal surface for which the c

Question

A block of wood (M_block = 7.9 kg) rests on a horizontal surface for which the coefficient of kinetic friction is 0.22. A bullet_(m_bullet = 32 g) is shot along the horizontal direction and embeds in the block, displacing the block 80 cm. What is the magnitude of the acceleration of the bullet and block from immediately after the impact until they come to a stop? What is the magnitude of the velocity of the bullet and block immediately after the impact? What was the magnitude of the initial velocity of the bullet immediately before the impact?

Explanation / Answer

(a)

Acceleration of the block is a = - (mu)*g = - (0.22)(9.8 m/s^2) = -2.156 m/s^2

(b)

The relation between velocity and acceleration and displacement is,

          v^2 - v0^2 = 2as

          0 - v0^2 = 2as

                    v = sqrt ( 2as)

                    v = sqrt ( 2*2.156 m/s^2*0.80 m)

                    v = 1.86 m/s

(c)

Apply conservation of linear momentum to the bullet and block system.

      m*v1 = (M+m)v

         v1 = (M+m)v / m

         v1 = (7.9 kg +0.032 kg) (1.86 m/s) / 0.032

         v1 = 14.7 m/s

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.