(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

http://www.diigo.com/item/image/2sb3i/ahcq [Broken]

2. Relevant equations

Ʃ[itex]\vec{F}[/itex] = m[itex]\vec{a}[/itex]

3. The attempt at a solution

For M :

T - mg = ma

T - 19.6 = 2a (1)

For 2M :

40 cos (150) - T = 4a

from (1) : T = 2a + 19.6

substituting :

40 cos (150) - (2a +19.6) = 4a

40 cos (150) - 19.6 = 6a

a = [itex]\frac{40 cos (150) - 19.6}{6}[/itex] = -9 m/s^2

but the right answer is 2.5 m/s^2.

if I replace 150 with 30 the answer will be correct

but it's 150 with respect to the positive x axis.

what is the wrong please??

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# Homework Help: Newton's 2nd law problem

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