physics question

2010-06-25 10:36 pm
A rocket fires two engines simultaneously. One produces a thrust of 725 N directly
forward,while the other gives a 513N thrust at 32.4degrees above the forward direction. find the magnitude and direction(relative to the forward direction) of the resultant force that these engines exert on the rocket.

Anybody clarify the concept for me?
List the steps
The ans is 1190N and 13.4degrees

回答 (1)

2010-06-26 3:55 am
✔ 最佳答案
Use vector addition. First draw out the vector triagnle. Then apply cosine formula, let F be the resultant force,

F^2 = 725^2 + 513^2 - 2 x 725 x 513 x cos(180-32.4) N^2
hence, F = 1190 N

Apply sine formula, let a be the angle at which F makes with the forward direction,
sin(a)/513 = sin(180-32.4)/1190
solve for a gives a = 13.4 degrees.



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