Post a New Question

physics

posted by .

At a picnic, there is a contest in which hoses are used to shoot water at a beach ball from three directions. As a result, three forces act on the ball, F1, F2, and F3 (see drawing). The magitudes of 1 and 2 are F1 = 55.0 newtons and F2 = 95.0 newtons. Using a scale drawing and the graphical technique determine the following such that the resultant force acting on the ball is zero.

i'm not sure how to start this problem
help pleasee

  • physics -

    Figure out the East-West forces and add them up:
    ... from F1: 40 cos(60 deg) = 20
    ... from F2: -90
    ... from F3: F3 cos(theta)
    Add them up:
    ... -70 + F3 cos(theta)
    Set it equal to zero (the ball does not move)
    ... 70 = F3 cos(theta)

    Now do the same for the North-South forces. You should get
    ... 34.641 = F3 sin(theta)

    We have two equations in two unknowns. We can solve them, first for the angle:

    34.641 / 70 = [-F3 sin(theta) ] / [F3 cos(theta) ]
    0.4949 = -tan(theta)
    Using arctangent, we find
    theta = 26.33 degrees.
    And cos(theta) = 0.896
    and sin(theta) = 0.444

    Putting these back into the first two equations:
    70 = F3 cos(theta)
    70 / 0.896 = F3 = 78.102
    And also
    34.641 = F3 sin(theta)
    34.641 / 0.444 = F3 = 78.102

  • physics -

    the answer above is for another calculation so plug in you values and derive your answer

Answer This Question

First Name:
School Subject:
Answer:

Related Questions

More Related Questions

Post a New Question