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AS Physics - Resolving physics - is the website wrong or have I gone mad watch

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    I've been looking at the car question on this page (2nd worked example) for too long now, I don't see how the component parallel to the slope = 10 000 cos 60°. Surely it is 10 000 divided by cos 60°?

    Question: http://www.s-cool.co.uk/a-level/phys...nto-components
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    (Original post by Sint)
    I've been looking at the car question on this page (2nd worked example) for too long now, I don't see how the component parallel to the slope = 10 000 cos 60°. Surely it is 10 000 divided by cos 60°?

    Question: http://www.s-cool.co.uk/a-level/phys...nto-components
    No. \cos 60^{\circ} = \frac{\text{adjacent}}{\text{hyp  otenuse}} = \frac{x}{10,000} where the parallel component is x. Like it says, look at the small triangle carefully - see what the adjacent to the angle is? See what the hypotenuse is? Remember the definition of cosine?
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    (Original post by Zacken)
    No. \cos 60^{\circ} = \frac{\text{adjacent}}{\text{hyp  otenuse}} = \frac{x}{10,000} where the parallel component is x. Like it says, look at the small triangle carefully - see what the adjacent to the angle is? See what the hypotenuse is? Remember the definition of cosine?
    Oh yeah thanks I see it now!
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    (Original post by Sint)
    Oh yeah thanks I see it now!
    No problem.
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    (Original post by Sint)
    I've been looking at the car question on this page (2nd worked example) for too long now, I don't see how the component parallel to the slope = 10 000 cos 60°. Surely it is 10 000 divided by cos 60°?

    Question: http://www.s-cool.co.uk/a-level/phys...nto-components
    Just to add, if you're not sure with a question, often you can think what would happen if the angle gets very small, or very close to 90 degrees. (i.e. compare what common sense tells you with your equations).

    In this case, if the slope goes all the way down to 0, it (should) be obvious that there's NO (gravitational) force parallel to the slope (since gravity is acting straight down). So you must be multiplying by 0, not dividing by it!
 
 
 
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