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Find the angle relitive to the x axis

  1. Oct 10, 2003 #1
    if anyone can please help me with these at least tell me how to start them that would be great...

    CJ5 4.P.013.] Only two forces act on an object (mass = 3.10 kg), as in the drawing. (F = 50.0 N.)the other force is 40N Find the magnitude and direction (relative to the x axis) of the acceleration of the object.
    ° (counterclockwise from the +x axis) (the angle inbetween the two forces is 45.)

    to find the angle relitive to the xaxis I used 40sin45.. then to find the magnitude, I used the pythagorean therom... c^2=50^2+40^2 yet my answers are wrong can anyone tell me where I went wrong???

    5. [CJ5 4.P.021.] On earth, two parts of a space probe weigh 11000 N and 4900 N. These parts are separated by a center-to-center distance of 24 m and may be treated as uniform spherical objects. Find the magnitude of the gravitational force that each part exerts on the other out in space, far from any other objects.
    N I used the equation: F=G(M1M2/r^2) I used the universial gravity constant.. 6.67259E-11(11000*4900/24^2) and still got the wrong answer.. is there more to the equation than what I am seeing?

    6. [CJ5 4.P.023.] Planet X has an equatorial radius of 4.80 107 m and a mass of 6.47 1026 kg.
    (a) Compute the acceleration of gravity at the equator of Planet X.
    (b) What it the ratio of a person's weight on Planet X to that on Earth?
    (weight on Planet X / weight on earth)


  2. jcsd
  3. Oct 11, 2003 #2
    In answer to the first question, draw an accurate forces diagram of the system involved. Then use measurement of the resultant force to give you a decent answer. You then have an answer to check your calculations against. Then see second part of the answer below:

    In answer to your second question, the 'm' in newtons equation refers to MASS not WEIGHT. You have used the 'weight on earth' value. If you want to do Physics questions correctly, don't just try to bang numbers into an equation. THINK about what you are asked, what values you have, and what you need to do. Your calculator should be the last thing you touch to get the answer, having 'solved it' first.

    The third one is a basic gravitational one using 'g' = Gm/r^2 .

    You really need to read up on the definitions of Mass, Weight, Gravitational Force and 'acceleration due to gravity'. Once you understand these concepts fully, the questions are very easy.
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