System Under Net Force
A system has a net force when an unbalanced force is exerted on it, in other words the sum of all forces is not zero. Acceleration and net force always exist together.
For example, consider the same system as above but suppose the object is now being lowered with an increasing velocity downwards (positive acceleration) therefore there exists a net force somewhere in the system. In this case, negative acceleration would indicate that .
In another example, suppose that two bodies A and B having masses and respectively are connected with each other by an inextensible string over a frictionless pulley. There are two forces acting on the body A: its weight pulling down, and the tension in the string pulling up. If body A has greater mass than body B, . Therefore, the net force on body A is, so .
Read more about this topic: Tension (physics)
Famous quotes containing the words system, net and/or force:
“The genius of any slave system is found in the dynamics which isolate slaves from each other, obscure the reality of a common condition, and make united rebellion against the oppressor inconceivable.”
—Andrea Dworkin (b. 1946)
“There is a potential 4-6 percentage point net gain for the President [George Bush] by replacing Dan Quayle on the ticket with someone of neutral stature.”
—Mary Matalin, U.S. Republican political advisor, author, and James Carville b. 1946, U.S. Democratic political advisor, author. All’s Fair: Love, War, and Running for President, p. 205, Random House (1994)
“Awareness of the stars and their light pervades the Koran, which reflects the brightness of the heavenly bodies in many verses. The blossoming of mathematics and astronomy was a natural consequence of this awareness. Understanding the cosmos and the movements of the stars means understanding the marvels created by Allah. There would be no persecuted Galileo in Islam, because Islam, unlike Christianity, did not force people to believe in a “fixed” heaven.”
—Fatima Mernissi, Moroccan sociologist. Islam and Democracy, ch. 9, Addison-Wesley Publishing Co. (Trans. 1992)