Additional Conservation of Momentum
Problems for kids considering Honors Chem
Problems taken from Giancoli’s Physics
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1. A 10,000 kg boxcar traveling at 15 m/s strikes a second car. The two stick together and
move off with a speed of 4.0 m/s What is the mass of the second car?
2. A 12,000 kg railroad car travels alone on a level frictionless track with a constant speed
of 18.0 m/s. A 6000 kg additional load is dropped onto the car. What then will be its
speed?
3. A halfback on an apparent breakaway for a touchdown is tackled from behind. If the
halfback has a mass of 80 kg and was moving at 4.1 m/s when he was tackled by an 85
kg cornerback running at 5.5 m/s, what was their mutual speed immediately after the
touchdown saving tackle?
4. An atomic nucleus at rest decays radioactively into an alpha particle and a smaller
nucleus. What will be the speed of this recoiling nucleus if the speed of the alpha particle
is 3.8 x 105 m/s? Assume the recoiling nucleus has a mass 57 times greater than that of
the alpha particle.
5. An atomic nucleus initially moving at 500 m/s emits an alpha particle in the direction of
its velocity, and the new nucleus slows to 450 m/s. If the alpha particle has a mass of 4.0
amu and the original nucleus has a mass of 222 amu, what speed does the alpha particle
have when it is emitted?
6. A 13 g bullet traveling 330 m/s penetrates a 2.0 kg block of wood and emerges going 270
m/s. If the block is stationary on a frictionless surface when hit, how fast does it move
after the bullet emerges?
7. A 4800 kg open railroad car coasts along with a constant speed of 7.50 m/s on a level
track. Snow begins to fall vertically and fills the car at a rate of 3.50 kg/min. Ignoring
friction with the tracks, what is the speed of the car after 90.0 min?
8. A 140 kg astronaut (including space suit) acquires a speed of 2.50 m/s by pushing off
with his legs from an 1800 kg space capsule. (a) What is the change in speed of the space
capsule? (b) I f the push lasts 0.500 sec, what is the average force exerted by each on the
other? As the reference frame, use the position of the capsule before the push.
Answers:
1. 2.8 x 104 kg
2. 12.0 m/s
3. 4.8 m/s
4. -6.7 x 103 m/s
5. 3.23 x 103 m/s
6. 0.39 m/s
7. 7.04 m/s
8. a. -0.194 m/s
b. 700 N