Kinematics

Rectilinear Motion
Rectilinear Motion is the motion which takes place along a straight line. There is no angular component related to it.

Displacement
Displacement is the change in position of an object with respect to a certain coordinate system or frame of reference.

Speed
Average Speed : The average speed in a time interval

Or Average Speed = 3xyz / [xy + yz + xz]

Instantaneous Speed : The speed of a particle at a certain point in time.

Velocity
Velocity is the rate of change of position of an object with respect to a specific co-ordinate system or frame of reference.

Average Velocity : The average velocity in a time interval.

Instantaneous Velocity : The velocity of a particle at a certain point in time.

Acceleration
The rate of change of velocity with respect to time is called as acceleration. Zero acceleration means uniform velocity. Positive acceleration means the velocity is increasing. Negative acceleration means velocity is decreasing.

Average acceleration : The average acceleration in a time interval

Instantaneous acceleration : The acceleration of a particle at a certain point in time.

Momentum
Momentum is the Product of Mass and Velocity.

p = mv

Force
The rate of change of momentum with respect to time is called Force. It can also be formulated by Mass x Acceleration.

F = ma

Kinematical Equations
v = u + at

s = ut + 1/2 at2

v2 = u2 + 2as

sn = u + (a/2)(2n - 1)

Motion of a Freely Falling Body
v = gt

h = 1/2 gt2

v2 = 2gh

hn = (g/2)(2n - 1)

Maximum height = u2 / 2g

Time of Flight = 2u / g

v = sqrt (2gh)

Relative Velocity
1) In the same direction ; a - b

2) In opposite directions ; a + b

3) If inclined at an angle θ, then

Relative Velocity = sqrt ( a2 + b2- 2abcosθ)

Motion
Motion in Straight Line : Moves along one co-ordinate axis

Motion in a Plane : Moves in a plane with 2 d co-ordinate axis.

Motion in Space : Moves in Space with 3 d co-ordinate axis.

Time is always uni-directional.

Change of Frame
If there are 2 different frames of reference w.r.t. which measurement is to be done, we use shift of origin concept of Maths.

Tips and Tricks

 * 1) Preferably make use of Kinematical Equations only.