In this Grade 8 Physical Science lesson from Chapter 13, students learn the scientific definition of work as the use of force to move an object a distance, distinguishing it from everyday uses of the term. The lesson covers how only the component of force acting in the direction of motion counts as work, and introduces the joule as the standard unit of measurement. Students also practice applying the formula W = Fd to calculate work in newton-meters using real-world examples.
Section 1
📘 Work is the use of force to move an object
This lesson introduces the scientific definition of work. You will learn that work requires both a force and movement, and discover how these two concepts are linked to accomplish tasks.
Section 2
Forces Do Work by Moving Objects
In science, work is only done when a force causes an object to move a certain distance. Pushing against a stationary wall requires effort but accomplishes zero scientific work because the wall does not move. For work to happen, force must cause displacement. Question: Is carrying a backpack across a room work?
Section 3
Force and Motion Must Align to Do Work
Only the part of a force that acts in the same direction as the object's motion does work. If you pull a wagon by its handle at an angle, only the horizontal part of your force does work to move it forward. The upward force does no work unless the wagon moves up.
Section 4
Scientists Calculate Work Using Force and Distance
You can calculate the amount of work done by multiplying the force by the distance over which the force is applied. The formula is W = Fd. If you use a 10-newton force to push a box 5 meters, you have done 50 newton-meters of work on that box.
Section 5
Scientists Measure Work in Joules
The standard unit for measuring work and energy is the joule (J). One joule is equal to the work done by a force of one newton acting over a distance of one meter (1 N·m). Lifting a small apple one meter high requires about one joule of work. This unit connects work to energy.
Section 6
Moving Objects Perform Work on Other Objects
Any object in motion can do work on another object by exerting a force that causes it to move. For instance, a gust of wind does work on a leaf by lifting it, and a river's current does work on a boat by pushing it downstream. This shows how energy is transferred through work.
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Section 1
📘 Work is the use of force to move an object
This lesson introduces the scientific definition of work. You will learn that work requires both a force and movement, and discover how these two concepts are linked to accomplish tasks.
Section 2
Forces Do Work by Moving Objects
In science, work is only done when a force causes an object to move a certain distance. Pushing against a stationary wall requires effort but accomplishes zero scientific work because the wall does not move. For work to happen, force must cause displacement. Question: Is carrying a backpack across a room work?
Section 3
Force and Motion Must Align to Do Work
Only the part of a force that acts in the same direction as the object's motion does work. If you pull a wagon by its handle at an angle, only the horizontal part of your force does work to move it forward. The upward force does no work unless the wagon moves up.
Section 4
Scientists Calculate Work Using Force and Distance
You can calculate the amount of work done by multiplying the force by the distance over which the force is applied. The formula is W = Fd. If you use a 10-newton force to push a box 5 meters, you have done 50 newton-meters of work on that box.
Section 5
Scientists Measure Work in Joules
The standard unit for measuring work and energy is the joule (J). One joule is equal to the work done by a force of one newton acting over a distance of one meter (1 N·m). Lifting a small apple one meter high requires about one joule of work. This unit connects work to energy.
Section 6
Moving Objects Perform Work on Other Objects
Any object in motion can do work on another object by exerting a force that causes it to move. For instance, a gust of wind does work on a leaf by lifting it, and a river's current does work on a boat by pushing it downstream. This shows how energy is transferred through work.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter