The velovity-time graph below is a record of the velocity of a car on a winding road. What is the magnitude of the acceleration at t = 3 seconds?

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?

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?