Two cars are driving toward each other at the same speed on a straight road. If they both turn around and drive at the same speed as before in the opposite direction, how will their velocities change? Neither car’s velocity will change.
The velocity of each car will change sign.
The velocity of the first car will change.
The velocity of the second car will change.

Why is rain likely when warm, moisture-laden air meets cold air? a) the lighter warm air will rise and cool down, causing condensation and rain. b) the cold air moves faster and pushes the warm air away, causing condensation and rain. c) the moisture in the warm air condenses on contact with the cold air, causing rain to fall. d) the cold air mixes with the warm air, reducing its temperature causing moisture to condense.