Physics--Ramp & Pulleys Problem

[sweetnsimple786]

So I've been trying to solve the same problem for over 90 minutes, and I'm pretty frustrated. The set up is you have a ramp and a pulley coming off from each end. The attached document has the image.

m₁ = m₂ = .20kg

The angle is 7^o = x

Acceleration, a, is 2.0m/s² in the direction of the first mass falling down

T₁ is found to be 1.56N and T₂ is found to be 2.36N. Use 9.8m/s² as g. To find m₃, I set up this equation:

m₃a = m₃gsinx + T₁ -T₂

But when I went to solve for m₃, I got a negative number... grr. I've asked so many people but they either haven't done it or can't find anything wrong with my equation.

Any help?

Edited September 18, 2009 by sweetnsimple786

[Nabih]

I think you are right but there is a mistake in the question. The acceleration couldn't be 2 m/s squared

If you take the system as a whole and frictionless incline then the acceleration of motion shoud be a = gsinx which is usual irrespective of the mass. and this value is 1.19 then there is a mistake in either the acceleration or in the angle. the angle is 12 and not 7.

[sweetnsimple786]

Okay.

I don't remember what I did for this lab... I think we redid it and got different numbers or something.

Thanks for trying to help.

Edited October 25, 2009 by sweetnsimple786

[Survival Robot]

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