Physics - Motion

 There are two types of physical quantity:

Scalar and Vector: Scalar (mass, speed, work, time, power)have magnitude only and Vector (displacement, velocity, acceleration, force) have magnitude and direction both.

** Electric current, though has a direction, is a scalar quantity because it doesn't obey triangular law.

Some Important formula of Motion:

Speed = Distance/Time

Velocity = Displacement/Time

Acceleration = Change in velocity/ Time (-ve acceleration is called retardation)

Equation of Motion:

v= final velocity, t=time

u=initial velocity, a= acceleration, s= distance/displacement

v=u+at, s= ut+1/2(at^2), v^2=U^2+2as

Average Velocity= (u+v)/2

Circular Motion:

If object moves with uniform speed, its motion is uniform circular motion. Uniform circular motion is an accelerated motion.

Angular Velocity w:  θ/t

 θ=s/r, so w=s/(rt)=v/r

Thus w=v/r and v=wr

Newton Law of Motion: 

1. First Law of Motion: book principia 1687

• It is also called Galileo or law of inertia.
• It gives the definition of force

Momentum= mass * velocity

2. Second Law of Motion:

The rate of change of momentum of body is directly proportion to applied force on body.

F=(mv1-mv2)/t = m(v1-v2)/t=ma

3.Third law of Motion:

To every action, there is an equal and opposite reaction.

** Impulse= f * T=change in momentum..