How Do You Calculate Acceleration with Different Masses and Friction?

[Chuck 86]

Homework Statement

The table is rough and has a coefficient of kinetic friction of 0.395. The three masses are m1 = 3.69 kg, m2 = 1.34 kg, and m3 = 1.82 kg, and the pulleys are frictionless. Determine the magnitude of the acceleration of each block.

EF=ma

The Attempt at a Solution

i set up force diagrams but i don't really know what I am suppose to find or how

 

[kuruman]

Hi Chuck86, welcome to PF.

There is no drawing with your question, but this sort of problem in general requires you to

1. Add all the forces in your fee body diagram to get the net force (what you call EF)
2. Set the horizontal component of the net force equal to the mass of your system times the horizontal component of the acceleration to get one equation.
3. Repeat with the vertical components of net force and acceleration to get a second equation.
4. Solve the equations for the unknown(s).

 

[Chuck 86]

thanks that helps but the forces that act on it are in m2: normal force, t1, t2, and the rate of gravity? m1&m3 : rate of gravity, and tension?

i tried to attach a copy of the picture

 

[kuruman]

I can't guess what the diagram looks like so until it is approved, try to do what you can.

 

[Chuck 86]

ok. i didnt know it needed approval

 

[kuruman]

Draw three free body diagrams, one for each mass. Write Newton's Second law for each of the diagrams. Note that the blocks have the same acceleration and that the tensions in the ropes are not equal. If they were, the block on the table would not accelerate. You will have three equations and three unknowns, the acceleration and the two tensions.