- #1
Tim Wellens
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Homework Statement
The question is about a block on an incline at an angle Θ above the horizontal. The block will begin from the resting position and travel from point A to B down the incline. Neglect friction.
1) As the block travels from point A to B, will the magnitude of the net force exerted on the block increase, decrease, or stay constant?
2) For each force identified in your free body diagram, state whether the work done on the block is positive, negative, or zero
Homework Equations
W=FdcosΘ
The Attempt at a Solution
1) I think the net force on the block, as it travels from point A to B, would remain constant because the variables that make up the forces stay constant. I think there will be a constant net force exerted on the block until the block comes to a rest. I think this net force would be ΣF=mgsinΘ because ΣFy=n-mgcosΘ=0 due to the lack of movement in the y direction, which makes the net force ΣF=mgsinΘ. This net force I think would stay the same?
2) The forces that I listed that act on the block are the normal force and the weight force. The normal force would have positive work done, i think, because if we use W=FdcosΘ.. then the force is positive because it would be mgcosΘ.. The force and distance will be positive, as is the angle. Or is the distance 0 because the block isn't traveling at all in the y direction?
The weight force I'm confused on because you can break the weight force up into components, the y component is negative and the x is positive. So, I'm not sure if the work done by the weight force would be negative, positive or zero..