Speed
Speed can be defined as the rate of change of position of an object moving in any direction. Speed is measured as the ratio of the distance covered by an object to the time in which the distance was covered. The speed of any body is considered to be a scalar quantity, with only magnitude and no associated direction.
[Tex]s=\frac{d}{t} [/Tex]
where, ‘s’ is the speed in m/s, ‘d’ is the distance travelled in m and t is the time taken in seconds.
CGS system | cm/s |
SI system | m/s |
Speed and Velocity
Mechanics can be termed as the branch of physics concerned with the concepts of energy and forces and their effect on bodies. It governs the relationships related to the motion of objects, that is, between matter, force, and its associated energy. It is responsible for the motion of bodies and the action of forces on these bodies as well. Practically, mechanics involve the design, construction, or operation of machines or tools. For instance, the distance covered by a car to stop travelling at a speed of 30 km/h.
The branch of classical mechanics concerned with the motion of points, object groups and systems, holding no reference to the motion of these objects, is called Kinematics, often termed the “Geometry of Motion.”
The sub-branch of physical science which is related to the motion of material objects under the effect of the physical factors affecting them, that is force, mass, momentum, and energy is called the Dynamics.
Rest
Anybody is said to be at a rest position if there is no change in its position (distance, displacement) with time, concerning its surroundings or a reference point.
Motion
The change in the position of anybody concerning time can be termed as motion. Any object under motion can be visualized by the naked eye by determining the change in the positional coordinates and then, associating it through the eye of the arbitrary observer. Motion can be computed in terms of both the position vectors, that is, the displacement, and distance, and taking into consideration the speed factors, that is, velocity, acceleration, speed, and time.
For instance, a spring ball attached to one end of a rod swinging at different time frames can be assumed to be in motion.