Levers

How are wheelbarrows can openers and bicycle brakes alike? Why is it easierto hold a bolt tight with a pair of pliers than with your bare hands? Why is iteasier... » 

How are wheelbarrows can openers and bicycle brakes alike? Why is it easierto hold a bolt tight with a pair of pliers than with your bare hands? Why is iteasier to eat a carrot with back teeth than with your front? Why is a seesawconsidered a machine? This book shows you how different kinds of these simplemachines are all around you to make your work and play easier. «