Thread: Physics help
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Old 03-08-2011, 05:59 PM
Yak Yak is offline
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Quote:
Originally Posted by TheDon View Post
(also made another mistake, used 1.67 M/S^2 not 1.17)

sum of all x = 3.50N +(-1.20N)+ F3x = 1.17m/s^2

sum of all y = 0+ 1.78N + F3y = -0.677m/s^2

object has mass 6.17 kg (I think this might need to be used since the sum of both values is in Newtons and I guess everything has to be the same unit to be able to work with them?)

and I got it

answer is 4.92N ,-5.96 N

I had to get the sum of all forces for each by multiplying 6.17KG by the a for x and the same for y.. then the rest was elementary mathematics.
Your answer appears correct, but you're mixing units. Force (N) can't equal acceleration (m/s^2).

Fx = 3.50N +(-1.20N)+ F3x = (1.17m/s^2 )(6.17 kg)
Fy = 0+ 1.78N + F3y = (-0.677m/s^2)(6.17 kg)

F3x = 7.22 N - 3.5 N + 1.2 N = 4.92 N
F3y = -4.18 N - 1.78 N = -5.96

F=ma. If you know that, you can derive all other physics equations, almost.
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