Mechanical Systems Review Grade 8 Questions with well explained answers

lever - A rigid bar that is free to move around a fixed point Pulley - A simple machine that consists of a rope that fits into a groove in a wheel fulcrum - fixed point on a lever effort force - the force you exert on a lever load - the mass of an object that is moved or lifted by a machine work - when you exert a force on an object that causes the object to move some distance in the direction of the force. Joules - unit for work inclined plane - A ramp or slope that reduces the force needed to move objects up and down heights; a simple machine. input work - the work you do on a machine output work - the work the machine does on the load mechanical advantage - the comparison of the force produced by a machine to the force applied to the machine. Speed - rate of motionwheel and axle - two turning objects are attached to each other at their centers and one causes the other to turn. gear - a rotating wheel object with teeth around its rim. Gear system - A group of 2 or more gears Driver Gear - the first gear that is attached to the power source. driven gear (follower) - second gear Gear ratio - A comparison of the amount of times the follower and driver gear turn. formula: follower/driver kinetic energy - Energy of motion. energy transmission - Energy is transferred from one place to another, and no energy is changed or converted. Efficiency - How much energy you gave to the machine that was transferred to the load by the machine. Subsystem - When a simple machine is part of a larger system. simple machine and examples - a machine with few moving parts, making it easier to do work (lever, pulley, wheel and axle, inclined plane, wedge, and screw, gears) wedge - shaped like an inclined plane, but is used differently. it is forced into objects