wedge - A ... is two inclined planes put back to back., screw - A ... is composed of spiral inclined planes., lever - A ... helps lift an object with less effort., inclined plane - An ... is a ramp. It is used to reduce the effort needed to raise or lower an object., pulley - A ... is made up of a wheel and a rope. It is used to raise loads., wheel and axle - A ... are a simple machine. It is used to move heavy loads.,

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