Distance, Displacement, Speed and Velocity
Speed:
Speed is the distance travelled per unit of time.
It is how fast an object is moving.
Speed is the scalar quantity that is the magnitude of the velocity vector. It doesn’t have a direction. Higher speed means an object is moving faster. Lower speed means it is moving slower. If it isn’t moving at all, it has zero speed.
The most common way to calculate the constant velocity of an object moving in a straight line is the formula:
S =\(\frac{{Dis\tan ce\,\,travelled}}{{Time\,\,taken}}\) =d / t
where,
S is the speed (sometimes denoted as v, for velocity)
d is the distance moved
t is the time it takes to complete the movement.
Units for Speed:
The SI units for speed are m/s (metre per second). In everyday usage, kilometre per hour or miles per hour are the common units of speed. At sea, knots (or nautical miles per hour) is a common speed.
Types of speed:
There are four types of speed and they are:
1. Uniform speed 2. Non-Uniform speed
3. Average speed 4. Instantaneous speed
Uniform speed:
An object is said to be in uniform speed when the object covers equal distance in equal time intervals.
Ex: motion of ball on a frictionless plane surface
Non-Uniform speed:
An object is said to be in non-uniform speed when the object covers a different distance in equal intervals of times.(or)equal distance in unequal intervals of time the body is said to be travelling with nonuniform (or) variable speed.
Ex: The motion of a train.
Instantaneous speed : The speed of a body at any instant known as the instantaneousspeed.speedometer of vehicle measures the instantaneous speed.