Two blocks of mass 3.50 kg and 8.00 kg are connected by a massless string that passes over a frictionless pulley. The inclines are frictionless and the angles with the horizontal is 35 degrees. Find a) the magnitute of the acceleration of each block and b) the tension in the string.

ans: 2.20 m/s^2, 27.4 N

I have no clue how to approach problem. I start with a free body diagram. Since the blocks are resting on a surface, then there is no acceleration along the y direction. The acceleration and the tension are going to be the same because they are connected by the same pulley.

sigma Fx = T + m1cos theta

ahh I'm so lost.

the graph: imagine a triangle, at the top is the pulley and on left incline (of triangle) is the 3.50 kg and on right incline is 5.00 kg. Both angles pointing toward each corner are 35 degrees.

First, note the component of weight parallel to the incline is mg*sinTheta.This is the force pulling each side of the rope.

Net force= (8-3.5)g sinTheta
this has to equal total mass*acceleration
8-3.5)g sinTheta= (3.5+5) * acceleration
solve for acceleration

For tension, consider the left block.
t-weightdown= ma
tension= weight down + ma
= 3.5*g*sinTheta+3.5*acceleartion

1 answer

  1. 2.20m/s 27.4N

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