4.21. Newton’s First Law http://www.ck12.org
FIGURE 4.41
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/82430Do You Get It?
Q: How does Jerod use Newton’s first law of motion to change the direction of his skateboard?
A: Pressing down on just one side of a skateboard creates an unbalanced force. The unbalanced force causes the
skateboard to turn toward the other side. In the picture, Jerod is pressing down with his heels, so the skateboard
turns toward his toes.
Summary
- Newton’s first law of motion states that an object at rest will remain at rest and an object in motion will remain
in motion unless it is acted on by an unbalanced force. - Using unbalanced forces to control the motion of a skateboard demonstrates Newton’s first law of motion.
Vocabulary
- Newton’s first law of motion: Law stating that an object’s motion will not change unless an unbalanced force
acts on the object.
Explore More
Do you think you understand Newton’s first law? Go to the URL below to find out. Review Newton’s law and watch
what happens to the skateboarder in the animation. Then answer the questions at the bottom of the Web page.
http://teachertech.rice.edu/Participants/louviere/Newton/law1.html