Work, Energy and Machines
I.
Work is done on an object only if the force and the direction of the motion are parallel. If these two quantities are not parallel we cannot discover the work done (if any).
Work is done on an object only if the force and the direction of the motion are parallel. If these two quantities are not parallel we cannot discover the work done (if any).The work done is positive if the force and motion are in the same direction.The work is negative if the force and motion are opposite one another.When force is applied at an angle the work W = Fd (cos theta).By comparing the energy of a system before and afterwards we can discover the work done.II.Energy is the ability to do work.
Energy is the ability to do work.Objects in motion have kinetic energy and KE = ½ mv2Objects that have stored energy due to position, composition or a restoring force that acts on them such as a spring, (elastic) are said to possess potential energy. GPE = mgh and EPE = ½ kx2
Mechanical energy is the total energy in a given system, the sum pf potential and kinetic.III.Energy will always be conserved.
Energy will always be conserved.It can be changed in form but it is a constant quantity and isn't created or destroyed.In the absence of friction, all mechanical energy is conserved.IV.The work done on any object is equal to the change in kinetic energy the object experiences.
The work done on any object is equal to the change in kinetic energy the object experiences. This is a statement of the Work-Energy theorem. Actually any energy change equals the work done. We can find work by calculating the change in energy the object experiences.Power is the rate of doing work or the rate of transferring energy.The units of power are joules per second, which is a watt.A KWh means 1000 J every second for 3600 seconds.V.Machines are devices that make work easier by transferring force or changing the direction and/or amount of force required to do work.
Machines are devices that make work easier by transferring force or changing the direction and/or amount of force required to do work.Machines are evaluated by measuring the advantage they give the user.MA, mechanical advantage measure the force used and produced.MA = output force / input forceIMA = Distance in/ Distance out measure the "perfect" machine, 100 % efficientEfficiencey measures how well that force is translated into work.Eff = work out / work in x 100 or MA/IMA
