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## Homework Statement

In the figure below, a box of ant aunts (total mass m1 = 1.15 kg) and a box of ant uncles (total mass m2 = 3.60 kg) slide down an inclined plane while attached by a massless rod parallel to the plane. The angle of incline is θ = 30°. The coefficient of kinetic friction between the aunt box and the incline is µ1 = 0.226. The coefficient of kinetic friction between the uncle box and the incline is µ2 = 0.113.

(a) find the tension in the rod

(b) Compute the common acceleration of the two masses

## Homework Equations

Fnet = ma

## The Attempt at a Solution

(a) Solved part a and got that the tension was .836722N (which was right)

but I don't think you need that for part b...

(b)

Drew a new FBD for the total system:

W = force down = (mass of m1 + mass of m2)g =46.5975 N

Normal force parallel to the ramp

Frictional force perpendicular to the ramp, going up it

Fnet perpendicular = Normal force - perpendicular component of the weight = N - 46.5975cos(30) = 0 (because it doesn't accelerate in the perpendicular direction)

N = 40.3546

the frictional force = coefficient of friction * normal force

*for the coefficient of friction I added the two coefficients given: .113 + .226 = .339 (not sure if this part was right...)*frictional force = 13.6802N up the ramp

so Fnet parallel to the ramp = ma = Parallel weight force - frictional force

Fnet = 46.5975a = 46.5975N * sin(30) - 13.6802

solve for a, which = .7064m/s^2, which wasn't right.

Any help with this second part would be great, thanks!