How Do You Solve These Introductory Physics Problems?

In summary, the conversation involves two physics problems, one involving trains and the other involving an elf shooting an arrow at a running orc. The first problem asks for the time it takes for train A to reach Philadelphia, the time the two trains pass each other, and the distance between Atlanta and the point where they pass each other. The second problem asks for the distance the arrow hits the orc and the time it is in the air. The conversation also touches on a controversial test question involving crack cocaine and pimps.
  • #1
Bison_Lover
1
0
Hello I have 2 problem for homework. I just started physics so these problems are probably quite easy however i was not at school today and was not taught how to do them. I don't even know wher to begin so any help would be great. Anyway the problems are:

1) Train A leaves Atlanta, heading towards Philladelphia, at a constant 92km/hr. Train B leaves Philadelphia at the same time, heading towards Atlanta, at a constant 58 km/hr. The two cities are 1250 km apart, and the tracks are strait. Find how long it takes for train a to get to Philly, How long after train A leaves do the two trains pass each other, and how far from atlanta do the two trains pass each other?

2)An elf shoots an arrow at a retreating orc. The orc is running away at a constant 16.8 m/s, and the arrow leaves the bow at a constant 32.4 m/s. If the orc is 42m away from the elf when the arrow is fired find how far away from the elf the aroow hits the orc, and how long is the arrow in the air for.

Thanks for your time guys.
 
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  • #2
An example for the second one:

Try to picture a distance-time graph... the orc is running away at a constant speed so you would see a line (going up towards the right)... you would also see the line represented by the arrow (which would be going much faster and so the line would be steeper). The point where both these lines intersect, the arrow will hit the orc. Try to model the situation using y=mx+b ... then you can solve for two equations.
 
  • #3
Bison_Lover said:
2)An elf shoots an arrow at a retreating orc. The orc is running away at a constant 16.8 m/s, and the arrow leaves the bow at a constant 32.4 m/s. If the orc is 42m away from the elf when the arrow is fired find how far away from the elf the aroow hits the orc, and how long is the arrow in the air for.
Don't you just love the context in which these questions sometimes come?
 
  • #4
A teacher in the Washington, D. C. (U.S.A) school system got into a heckofalot of trouble (and I hope will be fired!) for giving a test with questions that started:
"You have 28 ounces of crack cocaine and... "

"A pimp has three ho's ..."

!
 
  • #5
That's pretty cool actually... I wouldn't mind seeing something like that on a test... takes away some of the tension associated with writing tests.
 

1. What are the two physics problems that you need help with?

The two physics problems that I need help with are: 1) calculating the velocity of an object and 2) determining the acceleration of an object.

2. What information do you have for each problem?

For the first problem, I have the initial position and final position of the object, as well as the time it took to move between the two positions. For the second problem, I have the initial velocity and final velocity of the object, as well as the time it took to change velocities.

3. Can you provide any diagrams or equations for these problems?

For the first problem, the equation v = (xf-xi)/t can be used to calculate velocity, where v is velocity, xf is final position, xi is initial position, and t is time. For the second problem, the equation a = (vf-vi)/t can be used to determine acceleration, where a is acceleration, vf is final velocity, vi is initial velocity, and t is time.

4. Are there any specific units or conversions that need to be considered?

Yes, it is important to make sure that all units are consistent when using equations to solve these problems. For velocity, the standard unit is meters per second (m/s), and for acceleration, the standard unit is meters per second squared (m/s^2).

5. Can you provide an example for each problem?

For the first problem, if an object starts at position 10 meters and moves to position 30 meters in 5 seconds, the velocity can be calculated as (30-10)/5 = 4 m/s. For the second problem, if an object starts with an initial velocity of 2 m/s and ends with a final velocity of 8 m/s in 2 seconds, the acceleration can be calculated as (8-2)/2 = 3 m/s^2.

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