CK-12 Physical Science Concepts - For Middle School

http://www.ck12.org Chapter 4. Motion and Forces

Review

1. State Newton’s first law of motion.


2. You don’t need to push off with a foot against the ground to start a skateboard rolling down a bank. Does this
   violate Newton’s first law of motion? Why or why not?

FIGURE 4.42

3. Nina ran into a rough patch of pavement, but she thought she could ride right over it. Instead, the skateboard
   stopped suddenly and Nina ended up on the ground (seeFigure4.42). Explain what happened.


4. Now that you know about Newton’s first law of motion, how might you use it to ride a skateboard more safely?