8.1. Work http://www.ck12.org
- What definition is given in the video for energy?
- What is the definition given in the video for work?
- What unit is used in the video for work?
Visit the following website and answer the questions for practice at calculating work.
http://www.sparknotes.com/testprep/books/sat2/physics/chapter7section6.rhtml
Review
Questions
- How much work is done by the force of gravity when a 45 N object falls to the ground from a height of 4.6 m?
- A workman carries some lumber up a staircase. The workman moves 9.6 m vertically and 22 m horizon-
tally. If the lumber weighs 45 N, how much work was done by the workman? - A barge is pulled down a canal by a horse walking beside the canal. If the angle of the rope is 60.0°, the force
exerted is 400. N, and the barge is pulled 100. m, how much work did the horse do?
- work: A force is said to do work when it acts on a body so that there is a displacement of the point
of application, however small, in the direction of the force. Thus a force does work when it results in
movement. The work done by a constant force of magnitudeFon a point that moves a distancedin the
direction of the force is the product,W=F d. - joule:The SI unit of work or energy, equal to the work done by a force of one Newton when its point of
application moves through a distance of one meter in the direction of the force.