When a bullet with a mass of 10G hits a wooden block with a mass of 24g at a horizontal speed of 300m / s, if the bullet stays in the wooden block, what is the speed of the wooden block? (2) If the bullet penetrates the block, and the speed of the bullet is 100 m / s, what is the speed of the block?

When a bullet with a mass of 10G hits a wooden block with a mass of 24g at a horizontal speed of 300m / s, if the bullet stays in the wooden block, what is the speed of the wooden block? (2) If the bullet penetrates the block, and the speed of the bullet is 100 m / s, what is the speed of the block?

(1) In the process of bullet hitting wood block, the momentum conservation of the system takes the direction of initial velocity of bullet as the positive direction. According to the law of momentum conservation, MV0 = (M + m) V, that is, 0.01 × 300 = (0.01 + 0.024) V, and the solution is v = 88.23m/s; (2) in the process of bullet penetrating wood block, the momentum conservation of the system takes the direction of initial velocity of bullet as the positive direction. According to the law of momentum conservation, MV0 = MV '+ MV, that is, 0.01 × 300 = 0 01 × 100 + 0.024v, the solution is: v = 83.3m/s; answer: (1) if the bullet stays in the block, the speed of the block is 88.23m/s; (2) if the bullet penetrates the block, the speed of the bullet is 100M / s, and the speed of the block is 83.3m/s