FORCE

A Force is that physical cause which changes or tends to change either the size or shape or the state of rest or motion of the body.

 From the point of view of an application, they are 2 types, Contact and Non-Contact forces. SI Unit of Force – Kg ms^-2 or N (Newton). 

Contact Forces | Non-Contact Forces

Frictional Force | Normal Reaction Force | Tension Force | Spring Force

Gravitational Forces | Electrostatic Force | Magnetic Force

Uniform Circular Motion

The movement of an object in a circular path, with a constant speed, is known as uniform circular motion.

A bike moving around a circular path is in a circular motion. The bike moving in a circular path with uniform speed is known as uniform circular motion.

Circular Motion

WORK POWER AND ENERGY

Everyday meaning of work is some activity that requires physical or mental effort. But according to physics, the definition of work is more precise and unambiguous. In Physics, if a force displaces an object, the work is said to be done.

The SI unit of work done = Newton(N) X metre(m) = joule(J)Energy is the capacity to do work. Energy is the cause and work is an effect. Therefore both work and energy have the same units, which is joule (J) in the SI system and erg in the CGS system. Kinetic energy and potential energy are the two main types of energy.

Power is the work done in a unit of time. In other words, power is a measure of how quickly work can be done.

MACHINES

Simple machines can be regarded as the elementary “building blocks” of which all more complicated machines are composed. They can be defined as the simplest mechanisms that use mechanical advantage (also called leverage) to multiply force.

Inclined Plane

An inclined plane is a sloping surface that behaves like a simple machine whose mechanical advantage is always greater than 1.

Pulley

A Pulley is one of the original simple machines.

The original primary use for pulleys was to make it easier to lift heavy items. A pulley is a simple machine made with a wheel and a rope, cord, or chain.

Pulleys can be found everywhere, helping us in making our tasks easier. In addition to lifting things, pulleys can be used singly or with many pulleys working together in order to transport people or things.

Single fixed pulley | Single movable pulley | Combination of pulleys | Block and tackle system

Levers

The axis, about which the lever turns, passes through a point of the lever which is called the fulcrum (F)
This point does not move, but remains fixed when the lever is in use

A lever is a rigid, straight or bent bar which is capable of turning about a fixed axis

Principle of lever

Moment of load about fulcrum = moment of effort about fulcrum