Aboxer misses the punching bag and punches the wall. he hurts his hand when the wall stops his fist. this is an example of newton's law.

Amplitude is a measure of a waves a; speed b; distance c; energy d; frequency

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?