1. POD: What does the momentum-impulse theorem tell us about…
the relationship between
momentum and stopping time?
stopping time and force of impact?

3. POD:
Two tractor-trailers are traveling 55.0 mph (1 mi = 1,609 m) on I-95 S. Truck #1 is half the mass of truck #2 because it is not carrying any cargo. As they go around the curve near Cottman Ave, they don’t expect to see traffic at a halt because of a recent accident. To avoid creating another accident, they both slam on their brakes with a force of 25,000 N.
How long will it take each truck to stop before hitting the car in front of them if the mass of truck #1 is 2,500 kg?
What conclusion can you make about the relationship between momentum and stopping time?

4. Summarize in your own words.
Fans of boxing frequently observe this same principle of minimizing the effect of a force by extending the time of collision. When a boxer recognizes that he will be hit in the head by his opponent, the boxer often relaxes his neck and allows his head to move backwards upon impact. In the boxing world, this is known as riding the punch. A boxer rides the punch in order to extend the time of impact of the glove with their head. Extending the time results in decreasing the force and thus minimizing the effect of the force in the collision. Merely increasing the collision time by a factor of ten would result in a tenfold decrease in the force.

5. EC if solved by Friday and show all work
There are 5 ships, 5 ports, 5 chimney colors, 5 departure times, & 5 goods.
Which ship goes to Port Said? Which ship carries tea?
1. The Greek ship leaves at six and carries coffee.
2. The ship in the middle has a black chimney.
3. The English ship leaves at nine.
4. The French ship with a blue chimney is left of the ship that carries coffee.
5. To the right of the ship carrying cocoa is the ship going to Marseille.
6. The Brazilian ship is heading for Manila.
7. Next to the ship carrying rice is the ship with a green chimney.
8. The ship going to Genoa leaves at five.
9. The Spanish ship leaves at seven and is right of the ship going to Marseille.
10. The ship with a red chimney goes to Hamburg.
11. Next to the ship leaving at seven is the ship with a white chimney.
12. The ship on the end carries corn.
13. The ship with a black chimney leaves at eight.
14. The ship carrying corn is anchored next to the ship carrying rice.
15. The ship to Hamburg leaves at six.

6. French tea blue Genoa
Greek coffee red Hamburg
Brazilian 8.00 cocoa black Manila
English rice white Marseille
Spanish corn green Port Said

7. POD:
Two farmers were bored so they decided to race their tractors down a cornfield. It just so happens that both farmers were 90.7 kg and their John Deere tractors both had a mass of 1,751 kg. Tractor #1 had a speed of 28 mph (1 mi = 1,609 m) and tractor #2 had a speed of 32 mph just before reaching the end of the field.
How long did it take each tractor to stop in time to avoid hitting the cows at the end of the field if they both applied a braking force of 8,888 N?
What conclusion can you make about the relationship between speed and stopping time?

8. Summarize in your own words.
Air bags are used in automobiles because they are able to minimize the effect of the force on an object involved in a collision. Air bags accomplish this by extending the time required to stop the momentum of the driver and passenger. When encountering a car collision, the driver and passenger tend to keep moving in accord with Newton's first law. Their motion carries them towards a windshield that results in a large force exerted over a short time in order to stop their momentum. If instead of hitting the windshield, the driver and passenger hit an air bag, then the time duration of the impact is increased. When hitting an object with some give such as an air bag, the time duration might be increased by a factor of 100 thus decreasing the force by a factor of 100.

9. POD:
During last year’s NASCAR Sprint Cup, two racecars passed the finish line at the exact same time and they were both traveling an average speed of 202 mph (1 mi = 1,609 m). As they crossed the finish line, they both started braking with a force of 33,000 N. The mass of car #1 was 1.25 times greater than the mass of car #2.
How long did it take each car to stop if the mass of car #2 was 704 kg?
What conclusion can you make about the relationship between mass and stopping time?

10. Summarize in your own words.
In racket and bat sports, hitters are often encouraged to follow-through when striking a ball. High-speed films of the collisions between bats/rackets and balls have shown that the act of following through serves to increase the time over which a collision occurs. This increase in time must result in a change in some other variable in the impulse-momentum change theorem. Surprisingly, the variable that is dependent upon the time in such a situation is not the force. The force in hitting is dependent upon how hard the hitter swings the bat or racket, not the time of impact. Instead, the follow-through increases the time of collision and subsequently contributes to an increase in the velocity change of the ball. By following through, a hitter can hit the ball in such a way that it leaves the bat or racket with more velocity (i.e., the ball is moving faster). In tennis, baseball, racket ball, etc., giving the ball a high velocity often leads to greater success.

11. POD:
During a street race in Fast and Furious, two guys race in the middle of the night to prove their manliness. It just so happens that both guys are kg and their cars are both 1,000.0 kg. Car #1 has an average speed of 110 mph (1 mi = 1,609 m) and car #2 has an average speed of mph. In the middle of the race, they see a group of cop cars approaching them so they slam on their brakes with a force of 4,000.0 N.
How long does it take each car to come to a stop?
What conclusion can you make about the relationship between momentum and stopping time?

12. Summarize in your own words.
Nylon ropes are used in the sport of rock-climbing for the same reason. Rock climbers attach themselves to the steep cliffs by means of nylon ropes. If a rock climber should lose her grip on the rock, she will begin to fall. In such a situation, her momentum will ultimately be halted by means of the rope, thus preventing a disastrous fall to the ground below. The ropes are made of nylon or similar material because of its ability to stretch. If the rope is capable of stretching upon being pulled taut by the falling climber's mass, then it will apply a force upon the climber over a longer time period. Extending the time over which the climber's momentum is broken results in reducing the force exerted on the falling climber. For certain, the rock climber can appreciate minimizing the effect of the force through the use of a longer time of impact.

13. Refer to Chapter 6: Section 1 if necessary.
Using your current knowledge of physics, what do you the think the conservation of momentum is?
Refer to Chapter 6: Section 1 if necessary.