1) If the force to slide one box on the floor is 10 pounds and you stack two other boxes of the same weight on top, what force is needed to slide them?
10 pounds, because friction is independent of weight
20 pounds, because you added two boxes
30 pounds, because friction is proportional to weight
2) What can change the force of friction?
Changes in the normal force and coefficient of friction
Changes in the perpendicular friction and deformations
Changes in the way you measure factors
3) How common is plasma on the earth?
plasma is very rare
plasma is found inside of volcanoes and is plentiful there
both 1 and 2
4) Which of the following it true about water freezing to become a snowflake?
The rate at which it freezes affects how the crystals are formed.
It only affects how heavy the snow is.
Cold temperatures cause snowflakes to shrivel up.
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