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Copperhead2
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Homework Statement
A block is at rest on a ramp on a table with no friction between the surfaces. The ramp has an incline of 30 degrees. The mass of the block is 4kg, and the mass of the wedge is 6kg. What magnitude force can be applied to the opposite side of the ramp such that both the ramp and the block accelerate without the block sliding?
Homework Equations
F = ma
m * gravity * sin(theta) = ma
normalForce = mg cos(theta)
forceByGravity = mgsin(theta) = ma
Force(block in x direction) = 4(-a) //negative a because it's going left.
Force(ramp in x direction) = 6(-a)
The Attempt at a Solution
My first thought was to figure out the acceleration the block would have without a push from the ramp (though since the block starts at rest I'm not sure how relevant this information is):
mgsin(theta) = ma
(4)(9.8)(sin30) = (4)a
a = 4.9 m/s^2
and that the force from the ramp would match up to have the same acceleration (i.e. F = ma = 6*(-4.9) ), but I think there's something conceptual about this that I'm not taking into account because I'm unable to explain exactly why that would work. Should the push force act similarly to friction in this model? What should I try to do?