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Homework Help: Test tommorow need help

  1. Sep 25, 2005 #1
    test tommorow need help plz

    i have a test tommorw and i need answeres to the folowing questions if u can help i would be very thankful
    a bout can travel at 1.85 m/s in still water at wat angle must it go in order to go stright across a 110 m river flowing at 1.20m/s
    if it goes stight across detrime the time it would take
    if it goes stright across how far down streem would it end up


    a child throws a baseball onto the roof a house then catches it 1.0 m from the ground the roof has an angle of 33 and from the ground to the tip of the roff the distance is 6.2 m is the ball fals at a speed of 3.2 m/s
    how long is the ball airborne
    wat is the horizantal distance form the glove to the edge of the roof
    wat is the velocity of the ball just before it hits the glove

    plz i need help with this i have a test and i need to know it i really need ur help

    ps i only need the soloution to Q1 b,c and Q2 plz help i need to pass
  2. jcsd
  3. Sep 25, 2005 #2
    You've already posted this question and we're trying to help you. You don't need to double post.
  4. Sep 25, 2005 #3
    sry but i waited for 3 hours and still no help
  5. Sep 25, 2005 #4


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    Science Advisor
    Homework Helper

    Those are certainly some interesting questions.. My first step would be to read this sticky.
    If you show us what you have tried and where you are getting stuck, there are many here who can help steer you in the right direction.

    My second suggestion is to interact sooner with the forum (especially before exams), as it can easily take more than one day to get useful help.
  6. Sep 25, 2005 #5
    well i got the first part but now im stuck our teacher dosnt belive in giving formula sheets and as far as i got i dont have enogh info to get the time or displacment
  7. Sep 25, 2005 #6
    i drew the triangle but since this is vectores i dont know if i should add the negitive ot vf or just leav it likr that and i really dont know how to write the formulas on this so for me to do that would only take forever
  8. Sep 25, 2005 #7
    there are 10 questios in the review those are the only two i cant get
  9. Sep 25, 2005 #8
    the angle i got was 33 i used the pathgrione therom then used the sine law to figer it out but now im stuck
  10. Sep 25, 2005 #9
    Ok, let's take it one step at a time. You say you have part A to number one. How did you do this? Using some basic trig. Part B can be solved usingthe Phythagorean Theorem. The question did not say which way the water was flowing, so you could assume it was going either way, it would not make a difference as to the angle.

    I got a different answer for the angle. Are you familiar with inverse trig functions? What trig funtion: sine, cosine, or tangent can be used to relate the two pieces of information you have for part A? (HINT: You have the opposite leg and the hypotenuse)
    Last edited: Sep 25, 2005
  11. Sep 25, 2005 #10
    yeah but see umm u had to use the pathagriun therom to fin the hypatinous then use the sine law to find theda out of that and sry if i was sso late i had to eat diner
  12. Sep 25, 2005 #11
    the inverse would only get you the y or x componant
  13. Sep 25, 2005 #12
    and how would u get time with the pythagrin therom????
  14. Sep 25, 2005 #13
    Look at it this way.... [tex]\sin{\theta}=\frac{1.20}{1.85}[/tex] How can you find the angle?
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