if change in potential energy = change in kinetic energy the forumla is
PEi + KEi = PEf +KEf
but change in kinetic energy by itself is: KEf- KEi
and change in potential energy is: PEf-PEi
so should change in potential energy = change in kinetic energy therefore be
KEf-KEi =...
My question is for free body diagrams with tension on top and mass hanging from the bottom. Why is it "T-mg" sometimes and "mg-t" other times. How do I know which one to use? I was doing gravitation questions where "T-mg=Fc" sometimes and "mg-t=Fc" other times.
I'm having trouble solving this problem, someone want to help me out?
Two blocks are connected by a cord as shown:
Find the acceleration of the blocks.
http://img177.imageshack.us/img177/2554/physicshc9.jpg
I have the answer, but I don't know how to get to it.
the answer is 7.56