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Electromagnetism -

when a electronic current flows through the wire it produces a magnetic field around the wire. The magnetic field only gets produced when there is an electric current.

This effect uses electromagnetics , electromagnetics attract electric material(iron,steel,nickel, cobalt)

Electromagnetics are used on crane lifts to lift the metals and put them in a scap yard and recycling centers.

When the current flows through the circuit, the electromagnet makes a magnetic field.

The electromagnet attracts the springy metal arm.

The arm hits the gong, which makes a sound.

The circuit is broken now the arm is out of position.

The electromagnet is turned off and the springy metal arm moves back.

The circuit is complete again.

The cycle repeats as long as the switch is closed.

The Motor Effect-

A simple electric motor can be built using a coil of wire that is free to rotate between two opposite magnetic poles. When an electric current flows through the coil, the coil experiences a force and moves. This is called the motor effect.

This size of the force is greatest when the wire is perpendicular to the magnetic field of the permanent magnet. In other words, it cuts through the magnetic field at 90°. If the wire is parallel to the magnetic field, it will not experience any force.

Centre of Mass -

The mass is the amount of matter an object has. The centre of mass for a symmetrical shape can be found by where the axes of symmetry cross.

Finding the centre of mass from a suspending object-

The centre of mass for a irregular shape is found differently,

-Drill a small hole in the object and hang it up so that it is free to swing without obstruction.

-Hang a plumb line (a piece of string with a weight hanging from it) from the same suspension point. This lets you mark the vertical line directly below the suspension point.

-Drill another hole at a different location within the object.

-Again hang a plumb line to determine the vertical and mark it on.

-The point at which the two marked lines cross is the centre of mass.

Simple Pendulums-

This is a simple machine consisting of weight, suspended from a suspension point by a thin piece of material like a string or chain.

Examples of pendulums -

-Swings

-Fair rides

- Inside mechanisms of clocks, like a grandfather clock.

Calculating time periods for pendulums:

swing from one side to the other, and then back again to its original position.The number of complete swings (from one side to the other and back again) made by a pendulum per second is its frequency, f.

Time period and frequency are related by the equation:

T = 1/f

where:

T = time period in seconds, s

f = frequency in Hertz, Hz

Stability of object-

Measure of how likely it is for an object to topple over,The stability of an object is affected by two factors:

the width of the base of the object

the height of its centre of mass

Hydraulics

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