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Investigation Homework

  1. May 8, 2005 #1
    I was given this and i need help plz!

    Question 1:
    A person has a trip to of 144km to make.
    How long will the trip take at a speed of 144 km/h?
    How long will it take a speed of 2km/h?
    Construct a table showing the time taken (in hours) to complete the journey at 8 different speeds.
    Draw a graph of speed versus time-with speed on the horizontal axis and the time on the vertical axis.
    What is the rule connecting speed and time?

    Question 2:
    On a hot day a deer is standing in a narrow railroad tunnel, 80 metres from the west end of the tunnel.
    The deer sees a train approaching the tunnel from the west. the train is travelling at a constant speed - a speed that is 10 times as fast as the deer can run.
    The deer thinking quickly, realises that if she runs towards the train she will emerge from the tunnel when the train is 20 metres from the tunnel. However if she runs away from the train, she will be hit just as she reaches the end of the tunnel.
    How long is the tunnel?

    Question 3:
    Kym was about to get her maths test results. She was excited because her mother Irene had promised to give her 70 cents for every question she got right and Kym had to give back 30 cents for every question she got wrong. Kym came home all excited nad said to her mum "mum you owe me $12.00".

    How many possible questions were in the test?
    You should come out with atleast three answers.

    These are the questions can any1 help, if u give the answer plz try to give the working out as well. :blushing:
     
  2. jcsd
  3. May 8, 2005 #2

    honestrosewater

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    Post your work. How far have you gotten, and where are you having trouble?
    Can you answer these two?

    You need to figure out the relationship between speed and time before you can answer Question 2.

    Question 3: Can you find the two equations you need to solve this?
     
  4. May 8, 2005 #3
    i haven't started yet! i need help badly!
     
  5. May 8, 2005 #4

    honestrosewater

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    Well, people will help you, but we aren't allowed to do your homework for you.
    How many hours do you think it will take to travel 144km at a speed of 144km per 1 hour? After 1 hour, how far will you have travelled?
    How many hours do you think it will take to travel 144km at a speed of 2km per 1 hour? After 1 hour, how far will you have travelled?
     
  6. May 8, 2005 #5
    and i thought u wud give me answers!
     
  7. May 8, 2005 #6

    honestrosewater

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    Here are the rules for homework help: Read This Before Posting. If you decide to put in some effort, people here can help you through the problems.
     
  8. May 8, 2005 #7

    HallsofIvy

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    Well, you were wrong- we don't dislike you so much we would sabotage your education! If you cannot do questions like this- that depend on a fundamental understanding of what something like "kilometers per hour" means then your teacher needs to know that in order to help you. Don't try to trick your teacher into thinking you know things you don't!
     
  9. May 9, 2005 #8
    i can do these questions mate but i need help in how to do working out and then do the answers!
     
  10. May 9, 2005 #9
    can sum1 provide sum equations?
     
  11. May 9, 2005 #10
    q1: How long will the trip take at a speed of 144 km/h? 1 hour
    How long will it take a speed of 2km/h? 72 hours

    is this right?
     
  12. May 9, 2005 #11
    i think q2 is 200 m
     
  13. May 9, 2005 #12
    q3 i have no clue what to do?
    for q1 Draw a graph of speed versus time-with speed on the horizontal axis and the time on the vertical axis how do i do this? also What is the rule connecting speed and time? how do i find this?
     
  14. May 9, 2005 #13
    Yes.

    How did you get the answer?

    You need to find the the amounts of questions answered wrong and right. The situation is constarained by the money condition. Can you form an equation that illustrates the situation based on this?

    Speed and time are related to eachother by acceleration which tells you how the speed changes as time passes. In general the relation is v(t)=v_0+at where v_0 is the initial speed, a the acceleration and t the time. Think about how the speed changes with time in your assignment. What kind of curves do you think speed vs time should form?
     
  15. May 9, 2005 #14
    first two questions are pretty easy........

    they can be done by just looking at them and thinking.....well the third question can be done easily by some trial and error method...but it doesnt give us two equations that could solve 2 unknowns.....1 equation is...X*70-Y*30=1200.......can u frame one more eqaution?????????
     
  16. May 9, 2005 #15
    thanks for the help guys can u be more specific plz?

    inha what do u get for q2? i got it by 20*10=200
    what can i do instead?

    nomorevishnu what wud u get for q2?
    is the equation tested?
     
  17. May 9, 2005 #16

    honestrosewater

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    For Question 2, first try to figure out where the train is. Draw a line and label points the train, west end of tunnel, deer, and east end of tunnel, in that order. The distance from the deer to the west end of the tunnel is 80m- label it. When the deer reaches the west end of the tunnel, it will have travelled 80m. How far will the train have travelled in this time (speed of train = 10 times speed of deer)?
     
  18. May 9, 2005 #17
    don't worry guys i ahve figured every thing out by myself thanks for the help provided!
     
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