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Homework Help: I'm finding force and vectors extreemly difficult

  1. Oct 12, 2004 #1
    I'm about to GO bizerk, honestly, Physics Is driving me mad, I'm plucking my hair out like crazy :surprised :eek: :confused: :cry: :cry:
    I need help understanding the head to tail rule?
    I also need help solving the following questions (I have NOT come Here to get answers as they have already been provided to me) Your Assistance will b very helpful.
    Q.1 a car is being towed with a rope inclined at 20 degrees, to the horizontal the tension in the rope is 350N.
    work out the horizontal & verticle tension in the rope.
    This is what iv worked out
    Iv applied Trignometry SOHCAHTOA
    iv selected Sin20 x 350= 108(the answer is wrong)
    Q.2.A VAN is Travelling north at a speed of 28ms-1
    after turning a corner it is heading 40 degrees east of north at 25ms-1 work out the change in velocity of the van.
  2. jcsd
  3. Oct 12, 2004 #2
    for head to tail rule, imagine you have 2 match sticks,

    arrange the match stick in such a way that the head of the stick (call it S1) is touching the tail of the other one (S2).

    Now draw a stright line from the tail of S1 to the head of S2, that would be your new vector, S1 + S2.

    for Q1, Sin20x350 = 120, check your calculation. but everything else looks good.

    for Q2, I wish i have the webspace to host a diagram for you, but consider the new velocity to be the hypotenuse, and the old velocity to be the adj., you're basically trying to find the length of opposite.

    the direction of the chage in velocity should be such that if you add it with your intial velocity, you get the final velocity.

    Hope it helps.
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