Physics Course/Force


Force is a term used to describe a quantity that acts on an object to change object's state or to perform a task on the object. Example Force used to push or pull a cart or force used to break a stick

Force's Characteristics

Force's Pressure

Force exerts on a cross sectional area of a surface of an object is called Pressure

P = \frac{F}{A}

Work Done

The ability of a Force to carry out a task on an object is defined Work done on the object . Work done by a force on an object to move object over a distance s is defined as the product of Force and Distance move

W = F s = F v t = p v
W = F \int v(t) dt


The ability of a Force to carry out a task on an object over a period of Time .

E = \frac{W}{t} = F \frac{s}{t} = F v = F a t = p a
E = \frac{F}{t} \int v(t) dt

Types of Force

Motion Force

Motion Force is a force used to set an object in motion . Force to make an object move is calculated by

F = m a
F = m \frac{v}{t} = \frac{p}{t}

For any motion of speed v(t) caused by a force

F = m \frac{dv(t)}{dt}

Gravitational Force

Attraction's Force of the Earth to attract any object toward the Earth

g = G \frac{m}{r^2}
F_g = M g = G \frac{m M}{r^2}

ElectroMotive Force

ElectroMotive Force is the electric force that set stationary charge to move in a straight horizontal line

F_E = q E

ElectroMagnetoMotive Force

ElectroMagnetoMotive Force is the magnetic force that set the moving charge to move in perpendicular to the horizontal direction

F_B = \pm vB

ElectroMagnetic Force

ElectroMagnetic Force is the sum of the Electric Field Force and the Electric force

F_EB = F_E + F_B = q(E \pm vB)


Force is used to to describe a quantity that acts on matter to perform a task

  1. To cause an object to move or to set an object in motion . Example to push or pull a door
  2. To cause matter to change its state . Example change Solid to Liquid to Gas
Pressure Force acting on a surface P = \frac{F}{A}
Work Done Force capability to do perform a task on an object P = \frac{F}{A}
Energy Work done over time P = \frac{F}{A}
Force Definition Formula
Motion Force Force causes an object's motion F = m a = \frac{m v}{t} = \frac{p}{t}
Gravitation Force Earth's Force to pull an object toward the earth Fg = m g = G \frac{m M}{R^2}
Friction Force Force one surface exerts on another surface
Elastic Force Elastic Force of a Spring F = - k x
Electrostatic Force Force of attraction of two stationary Unlike Charge F_e = K \frac{Q_+ Q_-}{R^2}
ElectroMotive Force Force causing a stationary charge to move in straigh line F_E = Q E
ElectroMagnetoMotive Force Magnetic Force that cause moving charge to move up or down perpendicular to initial direction of travel F_B = Q v B
ElectroMagnetic Force The sum of Electrostatic Force and ElectroMagneto Force F_EB = F_E + F_B = Q (E + vB)
Last modified on 28 March 2013, at 15:38