Machines are the devices which make our work easier and faster.
1) Machines helps in gaining force. With the help of machines, small force can be used to overcome a large force e.g. screw jack can lift an object as heavy as car to change its tyres.
2) Machine can change the direction of the force so that force can be applied in a more convenient manner e.g. rope passing over a wheel make easy to lift water from well.
3) Machines helps in carrying out unsafe and dangerous tasks e.g. pair of tongs can be used to lift a piece of burning coal from fire.
Effort: An effort is the force applied to a machine to do mechanical work.
Load: Load is the force that a machine exerts on a given body to be moved.
Fulcrum : A fixed point about which the machine can turn. Mechanical advantage of the lever = MA = effort arm/ load arm.
A SmartTest on Simple Machines
Learnhive Lesson on Simple Machines