Physics 4.8 Free Body Diagrams (2 of 10) The Atwood Machine

In this video I will show the “traditional” and the free-body diagram methods of finding a=? of the atwood machine..

Next video in this series can be seen at:

[uzairhussain]

To intuitively understand first derivation, you can assume that the same two blocks are moving on horizontal line under the same external forces and instead of string they are glued to each other. Suppose the smaller mass m2 is on left and bigger mass m1 is on right. The force on m1+m2 towards right is m1g and the force on m1+m2 towads left is m1g. Taking the right as positive direction the net force on m1+m2 is m1g-m2g. Thus according to newton law the acceleration of m1+m2 is (m1g-m2g) /m1+m2.

The 2nd derivation is already intuitive.

[imabhishek]

I seen the first clear conceptual videos solutions

[skbrosworld]

Sir can u even substitute the tension in this video. I want tension force

[LyndaWilliamsSRJC]

Great videos BUT you should make the masses point particles and have the vectors to approximate scale - if the weight is falling then the weight vector must be longer than the tension vectors. Sadly, I can't assign these to my physics classes because of your doing them to incorrect scale.