Page 158 - WCS - Electrical

WORKSHOP CALCULATION & SCIENCE - CITS

CENTRIFUGAL FORCE

According to the Newton’s third law of motion, the force which acts opposite to the centripetal force, is known as
centrifugal force. It may be noted that the centrifugal force always acts away from the centre of the path i.e., the
centrifugal force always tends to throw the body away from the centre of circular path
Body at rest
When a body does not change its position, with respect to its surroundings, it is said to be at rest.
Body at motion
When a body changes its position, with respect to its surroundings, it is said to be in motion. The motion may be
linear if the body moves in a straight line or it may be circular when it moves in a curved path.
Terms related to motion Distance
Distance

Actual path travelled by the body or motion without direction
Displacement
When a body is in motion from one place to another, the displacement is the distance from the starting position to
the final position or shortest distance between two points
Speed
It is the rate of change of displacement of a body in motion. It has got no direction and it is a scalar quantity
Velocity
It is the rate of change of displacement of a body in motion in a given direction. It is a vector quantity and can be
represented both in magnitude and direction by a straight line. Velocity may be linear or angular. The unit of linear
velocity is meter /sec,

Difference between speed & velocity
P = BC Q.Sin θ
Q AC tan α = P + Q.cos θ
Speed Velocity

BC
P
P = BC The rate of change of place of an object is its The speed in a definite direction is called
Q.Sin
θ
P×
AC =
=
BC
Q×
tan
BC

Q.Sin
Q P = AC speed α = P + Q.cos θ θ Q AC velocity Distance covered
Q AC tan α = P + QxBC θ Speed =
Q.cos

Time
P =
P BC In the speed, direction is not indicated only the Both the magnitude and direction are expressed
AC
P× AC = Q× BC P = BC magnitude is expressed

Q
AC
P× AC = Q× BC Q = AC Speed = Distance covered Distance Definite direction
PxAC
Velocity =

P = QxBC speed = P = Distance covered Velocity = Time
Time
Speed =
BC

QxBC
Time
AC
P =
AC
Definite

Distance
P = PxAC Velocity = Sin = CD direction
θ

Definite

P = BC Acceleration Distance Time direction change in velocity 2
PxAC
Q
Velocity =
Time
BC Rate of change of velocity is known as acceleration or it is a = Time m/sec

BD
CD Cos θ =
Q
2
Sin θ = CD the change of velocity in unit time. Its unit is metre/sec .It is a vector quantity

Sin θ = Q a = change in velocity m/sec 2 1
Time
BD Q a = change in 2 velocity m/sec 2 2
2
Cos θ = BD R = P + Time 2.P.Q cos θ
Q +

Cos θ = Q
Q unit = m/s (metre per square second)
2
1
CD
CD
tan α = 1 = F = m  (v −u)  

2
2
2
BD
OB +
OD
R = P + Q + 2.P.Q cos θ u = Initial velocity in metre per second(m/sec) v = Final velocity in metre per second(m/sec)
t



2
2
2
R = P + Q + 2.P.Q cos θ s = Distance in metre (m)
Q.Sin

tan α = CD = CD t = Time in second (sec) θ 

−u)
 (v
=
tan α = CD OB + CD F = m  Q.cos −u)(v   θ 
BD
P + 
OD
t
=

OD OB + BD F = m   t  
Q.Sin θ tan α = Q.Sin θ
= P + Q.cos θ θ P + Q.cos θ
Q.Sin
=
P + Q.cos θ 145
tan α = Q.Sin θ θ 2 2

Q.Sin
θ
P +
Q.cos
α =
tan
P + Q.cos θ R = P + Q + 2.P.Q cos θ CITS : WCS - Electrical - Exercise 13
2 2
R = P + Q + 2.P.Q cos θ

2
2
R = P + Q + 2.P.Q cos θ