What are the four kinds of air uplift?

If a balloon is taken outside on a very cold day, what will occur?

An electric clothes dryer has a resistance of 8 ohms. it draws 30 a of current. what is the voltage, in volts, of the wall outlet that it is plugged into?

If two students are running down the hall toward each other, trying to get to class, and they have the same mass and acceleration, what will happen when they collide? will their forces cancel out or will each one experience a reaction?