Question 1 What name is given to speed in specified motion?
Question 2 Define Velocity?
Question 3 What is the S.I. unit of velocity?
Question 4 What is the difference between velocity and speed?
Question 5 When a body said to have uniform motion?
Question 6 How the velocity of a body can be changed?
Question 7 When a body said to have non-uniform motion?
Velocity
Velocity of a body is the distance travelled by it per unit time in a given direction.
Distance travelled in a given direction is called as displacement.
S.I. unit of velocity is m/s or km/hr.
Velocity is a vector quantity.
For Ex:25km/hr towards north.
The direction of velocity is same as the direction of displacement of the body.
Uniform velocity
A body has a uniform velocity if it travels in a specified direction in a straight line and moves over equal distances in equal interval of time,no matter how small these intervals may be.
Velocity of a body can be changed in 2 ways:
1)By changing speed
2)By changing direction
Non-uniform velocity
When a body does not cover equal distances in equal interval of time,the velocity is said to be non-uniform.
For Ex:car moving on circular road with constant speed.
Speed and velocity are equal in magnitude if body moves in a single line.
For Ex: A———————–B
1oom
50 sec
east
100
Speed = ——–
50
= 2 m/s
100
Velocity = ——–
50
= 2 m/s
If a body does not move in a single straight line,then speed and velocity of body are not equal.
For Ex: A—————->B 100 km,50 sec east
B—————-> A 100 km,50 sec west
200
Speed = ——–
100
= 2 m/s
0
Velocity = ——–
100
= 0 m/s
The average speed of a moving body can never be zero but average velocity of a moving body can be zero.