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302 Problems Section 1 (17pts)
- Write all answers in your bound journal
- Make it NEAT and in COMPLETE SENTENCES,
clearly identify which section you are working (using numbers)
- Box final answers if doing math.
- -4pt if you do not title and date the entry
- -1pt (per infraction) if you do not clearly identify the sections, or number the problems
- State Newton’s third law in your own words.
- Action and reaction forces always have the _____ strength and act in
_____ directions.
- You and a friend are sitting across from each other on chairs with
wheels. You push off each other and move in opposite directions.
Explain the following:
a.How does the force you feel compare to the force your friend
feels?
b. If your mass is greater than your friend’s mass, how do your
accelerations compare?
- A book rests on a table. The force of gravity pulls down on the book.
What prevents the book from accelerating downward?
- Give three examples of Newton’s third law in everyday life. List the
action and reaction forces in each example.
- What two things does an object require to have momentum?
- Consider an airplane at rest and a person walking through the airport.
a. Which has greater mass?
b. Which has greater velocity?
c. Which has greater momentum? Explain.
- Explain how impulse is calculated.
- Is the unit used represent impulse the same as the unit for
momentum? Explain.
- State the law of conservation of momentum in your own words.
- You and your little cousin are standing on inline skates. You push off
of each other and both move backwards.
a. Which of you moves back at a greater speed? Use the law of
conservation of momentum to explain your answer.
b. How does your impulse compare to your cousin’s impulse?
- When you jump, you move upward with a certain amount of
momentum. Earth moves downward with an equal amount of
momentum. Why doesn’t anyone notice the Earth’s motion?
- Determine the momentum of …
a. … an electron (m= 9.1 x10-31 kg) moving at 2.18 x 106 m/s
(9.1 x10-31 kg)*(2.18 x 106m/s) = 2.0 x 10-24kg*m/s
b. … a 0.45 Caliber bullet (m = 0.162 kg) leaving the muzzle of a gun at 860 m/s.
c. … a 110-kg professional fullback running across the line at 9.2 m/s.
d. … a 360,000-kg passenger plane taxiing down a runway at 1.5 m/s
- A bicycle has a momentum of 24 kg•m/s.
What momentum would the bicycle have if it had …
a. … twice the mass and was moving at the same speed?
6kg * 4m/s = 24kg*m/s
12kg * 4m/s = 48kg*m/s
b. … the same mass and was moving with twice the speed?
c. … one-half the mass and was moving with twice the speed?
d. … the same mass and was moving with one-half the speed?
e. … three times the mass and was moving with one-half the speed?
f. … three times the mass and was moving with twice the speed?
- According to the Guinness Book of World Records, the fastest recorded baseball pitch was delivered by Nolan Ryan in 1974. The pitch was clocked at 100.9 mi/hr (45.0 m/s). Determine the impulse required to give a 0.145-kg baseball such a momentum.
- Jerome plays middle linebacker for South's varsity football team. In a game against cross-town rival North, he delivered a hit to North's 82-kg running back, changing his eastward velocity of 5.6 m/s into a westward velocity of 2.5 m/s.
a. Determine the initial momentum of the running back.
b. Determine the final momentum of the running back.
c. Determine the momentum change of the running back.
d. Determine the impulse delivered to the running back.
- Kara Less was applying her makeup when she drove into South's busy parking lot last Friday morning. Unaware that Lisa Ford was stopped in her lane 30 feet ahead, Kara rear-ended Lisa's rented Taurus. Kara's 1300-kg car was moving at 11 m/s and stopped in 0.14 seconds.
a. Determine the momentum change of Kara's car.
b. Determine the impulse experienced by Kara's car.
c. Determine the magnitude of the force experienced by Kara's car.
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