CBSE Class 9 Answered

Speed
Speed is the distance travelled by a body in one second and is measured in metre per second (m s^-1)

Velocity
Velocity is the distance travelled by a body in a particular direction in unit time
Or
Velocity is defined as the rate of change of displacement. It is measured in metre per second (m s^-1)

Uniform Velocity
A body is said to travel with uniform velocity if it undergoes equal displacement in equal intervals of time, however small in a given direction

Non-uniform Velocity
A body is said to be moving with non-uniform or variable velocity if

• it covers unequal distances in equal intervals of time or
• it covers equal distances in unequal intervals of time or
• it covers equal distances in equal intervals of time, but its direction is changing.