Simple block kinematics problem

AI Thread Summary
The discussion revolves around a block kinematics problem involving a 75lbf block on an inclined plane with static and kinetic friction coefficients of 0.50. The main objective is to determine the block's acceleration under a 25 lbf force at different velocities: 8 fps up the plane, 15 fps down the plane, and at rest. Participants express confusion about the angle's cosine and sine values, questioning whether they refer to the angle with respect to the horizontal or vertical. The need for clarity on these trigonometric components is emphasized to solve the problem effectively. Understanding the forces acting on the block is crucial for determining its acceleration in each scenario.
jean28
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Homework Statement



Block A weighs 75lbf and the coefficients of static and kinematic friction between A and the plane are both 0.50. Determine the acceleration of A under the action of the 25 lbf force when the velocity at A is (a) 8fps up the plane, (b) 15 fps down the plane. (c) Zero.

Homework Equations



Sum of all forces = mass * acceleration

The Attempt at a Solution



I don't know where to start... the box is doing up a plane and it's cosine is 4/5 and its sine is 3/5.
 
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"Its cosine is 4/5 and its sine is 3/5". What is "its"?? Yes, I understand it is an angle but with the horizontal or vertical?
 

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