6.2 Conservation of Momentum
1. A bullet going 481 m/s imbeds in a stationary block of wood. The bullet and block combo are going 5.27 m/s after the collision, and the combo has a mass of 12.1 kg (Bullet and block). What was the mass of the bullet?
(0.133 kg)
2. A 65 kg person dives 3.68 m/s to the right off of a 23 kg cart. What is the velocity of the cart if the cart and person were initially at rest?
(10. m/s to the left)
3. 68 kg-Francois running 7.8 m/s jumps on a 45.3 kg cart already rolling at 2.3 m/s in the same direction. What speed are they going after he jumps on?
(5.6 m/s)
4. A 1240 kg Toyota Camry going 12.0 m/s to the east, strikes a 2530 kg SUV going west at 16.3 m/s. What is the velocity of the wreckage after the collision?
(6.99 m/s to the west)
5. A 65 kg person is riding a 23 kg cart to the right at 3.15 m/s. What speed must he dive off the cart, and in what direction, to give the cart a velocity of 22.3 m/s to the right?
(3.6 m/s to the left)
Help with the Quizlette:
1) A 6.10 g bullet going 830. m/s imbeds in a stationary 310. g block of wood. What is the velocity of the block of wood just after the collision? (16.0 m/s) <Video>
2) A 6.50 g bullet imbeds in a stationary 170. g block of wood. The bullet and block combo are going 21.0 m/s after the collision. What was the velocity of the bullet before the collision? (570. m/s) <Video>
3) A person at rest fires a 1.70 g rifle bullet to the right at 1320. m/s. The person recoils at 0.0290 m/s to the left after this. What must be the mass of the person? (77.4 kg) <Video>
4) A 52.0 kg person at rest fires a 1.80 g rifle bullet to the right. The person recoils at 0.0720 m/s to the left after this. What must be the velocity of the bullet? (2080 m/s) <Video>
5) A 61.0 kg person fires a 5.40 g rifle shell at 870. m/s. If the person is initially at rest on a frictionless surface, what is their recoil velocity after firing? (0.0770 m/s) <Video>
6) A 3500 kg car going 23.0 m/s strikes a 1400 kg car traveling in the same direction at 13.0 m/s from behind. The two cars stick together. What velocity are they going after the collision? (20.1 m/s) <Video>
7) A 3800 kg car (going an unknown velocity) strikes a 1100 kg car traveling in the same direction at 17.0 m/s from behind. The two cars stick together and have a velocity of 23.0 m/s. What velocity was the first car going before the collision? (24.7 m/s) <Video>
8) A 1200 kg car going 24.0 m/s strikes a 2600 kg car traveling in the same direction from behind. The two cars stick together and are going 19.0 m/s just after the collision. What velocity did the other car have before the collision? (16.7 m/s) <Video>
9) Two football players strike each other head on. Player 1 has a mass of 120. kg and is running 3.30 m/s to the East, and player 2 has a mass of 95.0 kg is running 6.20 m/s to the West. What is their post-collision velocity if they stick together? (Speed and direction) (0.898 m/s west) <Video>
10) Two football players strike each other head on. Player 1 has a mass of 110. kg and is running 3.50 m/s to the East, and player 2 has a mass of 85.0 kg is running to the West. If they stick together, and are together moving 1.90 m/s to the West after the collision, was the velocity of player 2 before the collision? (Speed and direction) (8.89 m/s west) <Video>
11) Bumper car A (340. Kg) with velocity 4.50 m/s East collides with the rear of car B (610. Kg) which has a velocity of 2.40 m/s East. After the collision, car A has a velocity of 1.40 m/s to the West. What is the velocity of car B after the collision? (Speed and direction) (5.69 m/s east) <Video>
12) Bumper car A (480. Kg) with velocity 3.90 m/s East collides with the front of car B (410. Kg) which has a velocity of 5.10 m/s West. After the collision, car B has a velocity of 1.50 m/s to the East. What is the velocity of car A after the collision? (Speed and direction) (1.74 m/s west) <Video>
13) 85.0 kg Thor is standing on a 35.0 kg cart, and is holding a 6.40 kg hammer. Everything is moving to the right at 3.40 m/s. What is the velocity of Thor and cart if he throws the hammer 25.0 m/s to the left? (Speed and direction) (4.91 m/s right) <Video>
14) 82.0 kg Thor is standing on a 25.0 kg cart, and is holding a 6.20 kg hammer. Everything is moving to the right at 2.40 m/s. What is the velocity of Thor and cart if he throws the hammer 18.0 m/s to the left? (3.58 m/s right) <Video>
15) 88.0 kg Thor is standing on a 42.0 kg cart, and is holding a 8.40 kg hammer. Everything is moving to the right at 4.30 m/s. After he throws the hammer, he and the cart are moving 6.60 m/s to the right. What speed and in what direction did he throw the hammer?(31.3 m/s left) <Video>
Help with the Practice Problems:
Practice 6.2 – Conservation of Momentum
1. a. A bullet going 560. m/s imbeds in a stationary block of wood. The 272 g bullet and block combo are going 26.0 m/s after the collision. What was the mass of the bullet? (12.6 g) <Video>
b. Big J Sandvik (at rest) fires a 2.80 g rifle bullet to the left at 530. m/s. He recoils at 0.0220 m/s to the right after this. What must be the mass of Big J Sandvik? (67.5 kg) <Video>
c. A 2960 kg Mazda Protégé going 34.0 m/s strikes a 1410 kg Ford Escort traveling in the same direction at 18.0 m/s from behind. The two cars stick together. What is the velocity of the cars as they are stuck together? (28.8 m/s) <Video>
d. Two football players strike each other head on. Player 1 has a mass of 110. kg and is running 3.20 m/s to the East, and player 2 has a mass of 85.0 kg is running 8.30 m/s to the West. What is their post-collision velocity if they stick together? (Speed and direction) (1.81 m/s west) <Video>
e. 85.0 kg Big J Sandvik is standing on a 35.0 kg golf cart, and is holding a 8.20 kg golf club. Everything is moving to the right at some speed. After he throws the club, he is moving on the cart 3.00 m/s to the right and the golf club is moving to the right at 41.0 m/s. What speed and in what direction was he, his cart and his club going to begin with? (5.43 m/s right) <Video>
2. a. A 3.5 g bullet going 960. m/s imbeds in a stationary block of wood. The bullet and block combo are going 17.0 m/s after the collision. What was the mass of the bullet and block combo? (0.198 kg) <Video>
b. Big J Sandvik fires a rifle bullet to the right at 870. m/s. He has a mass of 72.0 kg. If he is initially as rest on a frictionless surface, and has a recoil velocity of 0.0450 m/s to the left, what is the mass of the bullet? (0.00372 kg) <Video>
c. A 12.0 kg cat moving an unknown velocity to the right strikes a 13.0 kg cat traveling to the right at 15.0 m/s. The two cats stick together and have a velocity of 18.0 m/s to the right. What velocity was the first cat going before the collision? (21.3 m/s) <Video>
d. Bumper car A (470. Kg) with velocity 3.80 m/s East collides with the front of car B (420. Kg) which has a velocity of 5.20 m/s West. After the collision, car A has a velocity of 1.30 m/s to the West. What is the velocity of car B after the collision? (Speed and direction) (0.507 m/s east) <Video>
e. 71.0 kg Big J Sandvik is standing on a 28.0 kg golf cart, and is holding a 3.60 kg golf club. Everything is moving to the right at 1.10 m/s. After he throws the golf club, he and the cart are moving 2.50 m/s to the right. What speed and in what direction did Big J Sandvik throw the golf club? (37.4 m/s left) <Video>
3. a. A 6.20 g bullet going 860. m/s imbeds in a stationary 340. g block of wood. What is the velocity of the block of wood just after the collision? (15.4 m/s) <Video>
b. A person at rest fires a 1.30 g rifle bullet to the right at 1120. m/s. The person recoils at 0.0240 m/s to the left after this. What must be the mass of the person? (60.7 kg) <Video>
c. A 3520 kg car (going an unknown velocity) strikes a 1020 kg car traveling in the same direction at 15.0 m/s from behind. The two cars stick together and have a velocity of 21.0 m/s. What velocity was the first car going before the collision? (22.7 m/s) <Video>
d. Bumper car A (310. Kg) with velocity 4.60 m/s East collides with the rear of car B (540. Kg) which has a velocity of 2.50 m/s East. After the collision, car A has a velocity of 1.20 m/s to the West. What is the velocity of car B after the collision? (Speed and direction) (5.83 m/s east) <Video>
e. 95.0 kg Thor is standing on a 43.0 kg cart, and is holding a 5.20 kg hammer. Everything is moving to the right at 2.40 m/s. What is the velocity of Thor and cart if he throws the hammer 32.0 m/s to the left? (Speed and direction) (3.70 m/s right) <Video>
4. a. A 6.80 g bullet imbeds in a stationary 150. g block of wood. The bullet and block combo are going 24.0 m/s after the collision. What was the velocity of the bullet before the collision? (553 m/s) <Video>
b. A 55.0 kg person at rest fires a 0.0130 kg rifle bullet to the right. The person recoils at 0.0890 m/s to the left after this. What must be the velocity of the bullet? (377 m/s left) <Video>
c. A 3570 kg car going 21.2 m/s strikes a 1470 kg car traveling in the same direction at 15.0 m/s from behind. The two cars stick together. What velocity are they going after the collision? (19.4 m/s) <Video>
d. Two football players strike each other head on. Player 1 has a mass of 110. kg and is running 7.20 m/s to the East, and player 2 has a mass of 95.0 kg is running 4.30 m/s to the West. What is their post-collision velocity if they stick together? (Speed and direction) (1.87 m/s east) <Video>
e. 115 kg Thor is standing on a 23.0 kg cart, and is holding a 4.20 kg hammer. Everything is moving to the right at 1.40 m/s. What is the velocity of Thor and cart if he throws the hammer 15.9 m/s to the right? (Speed and direction) (0.959 m/s right) <Video>
5. a. A 4.50 g bullet going 770. m/s imbeds in a stationary 210. g block of wood. What is the velocity of the block of wood just after the collision? (16.2 m/s) <Video>
b. A 62.0 kg person fires a 5.90 g rifle shell at 820. m/s. If the person is initially at rest on a frictionless surface, what is their recoil velocity after firing? (0.0780 m/s) <Video>
c. A 3230 kg car going 24.0 m/s strikes a 2610 kg car traveling in the same direction from behind. The two cars stick together and are going 18.0 m/s just after the collision. What velocity did the other car have before the collision? (10.6 m/s) <Video>
d. Two football players strike each other head on. Player 1 has a mass of 120. kg and is running 5.10 m/s to the East, and player 2 has a mass of 99.0 kg is running to the West. If they stick together, and are together moving 1.50 m/s to the West after the collision, was the velocity of player 2 before the collision? (Speed and direction) (9.50 m/s west) <Video>
e. 105 kg Thor is standing on a 45.0 kg cart, and is holding a 8.30 kg hammer. Everything is moving to the right at 2.30 m/s. After he throws the hammer, he and the cart are moving 1.60 m/s to the right. What speed and in what direction did he throw the hammer? (15.0 m/s right)
<Video>
The instruction for this unit:
