i'm trying to learn this stuff on my own so please bear with me.(adsbygoogle = window.adsbygoogle || []).push({});

here's the problem:

you have two mass, a 10kg on a frictionless 35 degree inclined plane, which is attached to 20kg mass via a pulley cord to hang vertically. Whats the aceleration?

Solution:

for the box hanging freely they got this equation, 196N-T=20kg*acclerertion----i understand this

To get the equation for the box on the plane they did this:

98Nsin35=56N

98cos35=80N

out of these two results, 56n and 80N, they choose 56N to get the equation for the box which is T-56N=10kg*a

my question is why they they choose to use 56N and not 80N which would have resulted in the equation T-80N=10*a

continuing the solution the book has, they combined the two equations, 196N-T=20kg*a and T-56N=10kg*a to get this:

140N30kg*a

a=4.7 m/s/s I understand this part also.

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# Homework Help: Physics: Box sliding down an inclined plane

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