Define velocity. State SI unit, CGS unit? Type of quantity. write the expression.
The Correct Answer and Explanation is:
Definition of Velocity:
Velocity is defined as the rate of change of displacement of a body with respect to time. It indicates how quickly and in which direction an object is moving.
SI Unit:
Metres per second (m/s)
CGS Unit:
Centimetres per second (cm/s)
Type of Quantity:
Vector quantity (since it has both magnitude and direction)
Expression:Velocity=DisplacementTime=st\text{Velocity} = \frac{\text{Displacement}}{\text{Time}} = \frac{s}{t}Velocity=TimeDisplacement=ts
Explanation
Velocity is a fundamental concept in physics that describes the motion of an object. It is a vector quantity, meaning it possesses both magnitude and direction. The magnitude tells how fast the object is moving, while the direction specifies the path along which the object is traveling.
Displacement refers to the change in position of an object in a particular direction. When this displacement occurs over a period of time, the velocity is calculated using the formula:v=stv = \frac{s}{t}v=ts
where vvv is velocity, sss is displacement, and ttt is time taken.
Unlike speed, which only measures how fast something is moving regardless of direction, velocity also considers the direction of movement. For instance, if a car travels 60 km north in 2 hours, its velocity is 30 km/h north. However, if the same car returns to its starting point in the next 2 hours, the total displacement becomes zero, and thus the average velocity for the whole trip is also zero.
The SI unit of velocity is metres per second (m/s), which indicates how many metres an object moves in one second in a given direction. In the CGS system, the unit is centimetres per second (cm/s).
Velocity can be uniform or variable. Uniform velocity means the object covers equal displacements in equal intervals of time, without changing direction. In contrast, variable velocity implies that either the speed or the direction (or both) are changing over time.
Understanding velocity is crucial in various fields such as mechanics, astronomy, and engineering. It helps predict future positions of objects, design efficient transport systems, and study natural phenomena like planetary motion.
