Work
What is work?
Videos - Is It WORK?
Is It WORK?
WORK
NOT WORK
Marzano’s Vocabulary Sheet
USING PENCIL...
In the “TERM, PHRASE” box, write the term WORK.
Based on the two videos, write down what you think WORK
is in the “DESCRIPTION” box.
Force
A force is a push or pull in a particular direction.
Forces affect how objects move. They may cause motion;
they may also slow, stop, or change the direction of
motion of an object that is already moving.
Forces are measured
in Newtons (N).
More than one force can act on an object at a time.The
forces can push or pull in any direction. What happens to
the object when the forces act depends on two things:
● How strong the forces are
● The direction of the forces
Balanced and unbalanced forces
Two or more opposite forces are balanced forces if their
effects cancel each other and they do not cause a change
in an object’s motion. They cancel
each other out and the object
does not move.
If one force is stronger than the
other, the forces are unbalanced.
Unbalanced forces cause a change
in motion.
balanced and unbalanced forces
Work
Have you ever done hours of homework and thought, “That was a lot
of work.” In scientific terms, you have not done any work at all.
In science, work is defined as the action that results when a force
causes an object to move in the direction of the force. While reading
the chapter, you may have put a lot of mental effort into reading, but
you were not using force to move an object. Therefore, in the
scientific sense, you were not doing work.
Work in the scientific sense is a hard concept for many
people to understand. You know that work is done if the
following two conditions are met:
● The object moves as a force is applied.
● The direction of the object's motion is the same as
the direction of the force applied.
The first condition is easy to determine. In order for
work to be done, an object has to move because of the
force applied to it.
Look at the picture below. Is work being done?
If the truck never moves,
then work is not being
done.
It does not matter how
much force the girl applies
or how hard she tries to
push the truck. If it does not
move, no work is done from
the scientific point of view.
The second condition is a little harder to
determine. In order for work to be done, the
object must move in the same direction as the
force being applied to it.
Examine the picture below of the man carrying
the boxes. Is work being done?
To determine if work is being done, you must
determine the direction of the force and the
direction of the motion.
NO WORK
Look at the following pictures, and determine if work is being done.
In all the pictures assume that the object is in motion. Determine the
direction of force and the direction of motion in each picture and if
work is being done or not.
Direction --- Force
On
backpack
Motion
Doing Work?
Direction --- Force
Motion
Doing Work?
Now does this make sense?
WORK
NOT WORK
Situations of Work - is the person doing work?
1.
2.
3.
4.
5.
Lifting a book off of the table.
Holding a box in your hands.
Pushing on the wall.
Create a scenario where work is being done.
Create a scenario where work is not being done.
Remember to do work on an object, an object
must move in the direction of the force.
https://www.youtube.com/watch?v=iCqm5uxc2dE