1 acting on Particle 1 does work
W1 on Particle 1 and the kinetic energy of
Particle 1 changes by DKE1. Similarly for
Particles 2 to N.
The applet on Page 2
You can use the applet on Page 2 to investigate the work-kinetic energy theorem as it applies to a system consisting of two particles. The general theorem for a system of N particles is stated below. For more information on the work-kinetic energy theorem, see the information under Related Items.
The system of two "particles" in the applet on Page 2 is a binary star system. Open "Activities" under Related Items for suggestions on what to investigate with the applet.
Details on how to use the applet are available under Applet Help on the applet's Help menu.
The work-kinetic energy theorem for a system of particles
Let there be a system consisting of N particles, labeled 1
to N. Let us consider some time interval during
which the net force 1 acting on Particle 1 does work
W1 on Particle 1 and the kinetic energy of
Particle 1 changes by DKE1. Similarly for
Particles 2 to N.
The general work-kinetic energy theorem states that
W1 + W2 + ... +
WN = DKE1 + DKE2 + ... + DKEN.
(1)
Comment. In general, the work listed on the left-hand side of Eq.(1) contains work done both by internal and external forces. In the applet on Page 2, there are two internal forces doing work on the system. There are no external forces acting on the system in the applet. There are other systems in which there are only external forces doing work. Finally, there are systems with both internal and external forces doing work.