- #1
Eitan Levy
- 259
- 11
Homework Statement
The coefficient of friction between A and the table is μA.
The coefficient of friction between A and B is μB.
A, B, C and D all move with an acceleration of 2m/s^2 (A and B move to the left).
Find the force that the friction between the bodies apply on B.
Find the tension of the yarn that connects A and C.
Find the mass of D.
At a certain moment, the yarn which connects A and D is torn. Will A and B still move together? (Show with calculations)
mA=1.4kg ,mB=0.6kg, mC=2kg, μA=0.2, μB=0.75, a=2m/s^2
*Both times the static and dynamic coefficients are equal.
Homework Equations
F=ma
The Attempt at a Solution
The last question is what I am stuck in, but I don't have the answers so I will show my calculations prior to that.
Forces on A and B: (I hope everything is clear)
mBg=6N so NB=6N, now we could see that according to ma=F, 1.2=F, so the force is 1.2N.
Now if we look at C we could see that 4=TC-20, TC=24N.
Now if we look at A we could see that: mAg=14N, so NA=20N.
Using ma=F: 2.8=TD-1.2-24-0.2*20 so 2.8=TD-29.2, TD=32N
Looking at D: 2mD=10mD-TD, mD=4kg.
Now I am not sure what to do, I tried to draw the forces again, but from there I don't really know what to do. How can I know if C moves now? If it doesn't then A and B doesn't move, but if it does I don't know how to reach the answer.
Thanks in advance!