Work & Power

We have been studying work and power.  Work is what happens when energy acts on an object.  For example, a toaster uses electrical energy and converts it to heat energy.  The work done by a toaster is toasting bread.  It is a change in an object due to energy.  The way work is calculated when an object is moving up is by multiplying the mass of an object by the rate of gravity (9.8 meters per second squared) by the height the object is being lifted.  We have used the example of climbing the stairs at Trillium.  The height of the stairs is 4 meters and if a student has a mass of 60 kg, the work could be calculated by
W = 60 x 9.8 x 4.  The unit for energy and work is Joules.

Power is the rate at which work is done.  It can be calculated by dividing Work by time (P=W/t).  This concept is one that is very similar to our concept of power used by most students in every day language.  The more powerful a student was going up the stairs it meant they either moved more mass at the same time or moved the same mass at a faster time.  Power's units are watts.