Explain how air masses form and how they redistribute energy on earth surface

The boy of mass 30 kg is at r1= 2 meters from the fulcrum. of the girl is 45 kg, at what r2 must she sit so that they are balanced ?

Which is an example of gaining a static charge by conduction? a) rubbing a balloon against your hair. b) shuffling your shoes across a carpet. c) bringing a charged rod near an electroscope. d) touching your car on a cold day and getting a shock.

World class speed skaters can skate a 3,000-m course in about 4 minutes. what is their average speed for this course? a. 12.5 m/sb. 1.33 m/sc. 1.25 m/sd. 13.3 m/s