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Work W is the energy transferred to or from an object by means of a force acting on the object. Energy transferred to the object is positive work, and energy transferred from the object is negative work.
Work, Energy, and Power. “Energy cannot be created or destroyed: it can only be changed from one form to another.” —Albert Einstein. Kinematics and dynamics are about change. Simple observations of our environment show us that change is occurring all around us. But what is needed to make an object change, and where did that change go to?
Work (W) is equal to the amount of energy transferred or converted by the force. Work is a scalar. S.I. unit is also the joule (J). where F is applied force, s is object's displacement while the force is applied and θ is angle between applied force and displacement.
Review the units of work, energy, force, and distance. Use the equations for mechanical energy and work to show what is work and what is not. Make it clear why holding something off the ground or carrying something over a level surface is not work in the scientific sense.
PF1.5: WORK, ENERGY AND POWER. Energy exists in many different forms, eg, kinetic energy Ek, potential energy Ug, electrical energy, and elastic (or spring) energy Es. A fundamental principle of nature is that energy cannot be created or destroyed, only transformed or transferred.
2 Work, energy and power. The work done on an object by a constant force F is F ∆x cos Θ , where F is the magnitude of the force, ∆x the magnitude of the displacement and Θ the angle between the force and the displacement. W = F∆x cos θ. W scalar (no direction): A negative W is energy removed from object.
˜ is chapter presents the concepts of kinetic energy, work, and power and introduces some techniques that use these ideas, such as the work–kinetic energy theorem, to solve several types of problems.
