MHB Work energy principle and power

AI Thread Summary
The discussion focuses on a physics problem involving two particles connected by a string over a pulley. The tension in the string is expressed as T = 40m/(m+2) N, derived from simultaneous equations based on the forces acting on the particles. The work-energy principle is applied to determine how high particle X rises after being released, with the work done by tension calculated as W = T * 1.2 meters. There is a request for clarification on the definitions of tension (T) and acceleration (a) in the equations provided. The conversation highlights the importance of clear notation in problem-solving.
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Particle X of mass 2 kg , and particle Y of mass m kg are attached to the ends of a light inextensible string of length 4.8m. The string passes over a fixed smooth pulley and hangs vertically either side of the pulley. Particle X is held at ground level, 3m below the pulley. Particle X is released and rises while particle Y descends to the ground

a) Find an expression in terms of m for the tension in the string while both particles are moving.
By getting two equations
T-20=2a and T-10m=-ma
Solving simultaneously and removing a I got mT+2T-40m=0,
I finally got T=40m/(m+2) N
b) use work energy principle to find how close particle X gets to the pulley in subsequent motion.
Iam not able to get this ans. Pls help
 
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work done on the 2kg mass by the force of tension ...

$W = (T \, Newtons) \cdot (1.2 \, meters) = 2gH$, where $H$ is the highest point mass X rises above ground level.
 
skeeter said:
work done on the 2kg mass by the force of tension ...

$W = (T \, Newtons) \cdot (1.2 \, meters) = 2gH$, where $H$ is the highest point mass X rises above ground level.
Thanks!
 
The problem I have with
"a) Find an expression in terms of m for the tension in the string while both particles are moving.
By getting two equations
T-20=2a and T-10m=-ma"
is that you have not said what either "T" nor "a" are!

I can guess that "T" is the tension in the string and that "a" is the acceleration of the particles but you really should have said thar.
 
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