Question

When speed is stated along with its direction, it is called as
A) velocity
B) acceleration
C) jerk
D) none of these

Answer 1

Hint: Speed and velocity are related factors. The main difference is that in case of speed we will not specify the direction. Any object has an initial and final velocity. The final velocity is a vector quantity.

Complete step by step answer:
The speed of a substance is defined as the distance travelled by the object in a particular time. It can be mathematically represented as;
\[{\text{Speed = }}\dfrac{{{\text{Distance}}}}{{{\text{Time}}}}\]
This property of a moving object is irrespective of the direction in which it is moving and we are only calculating the distance it travelled.
But we have one more way to define the motion of a moving object and that property is called velocity. Velocity is given by;
\[{\text{Velocity = }}\dfrac
{{{\text{Displacement}}}}{{{\text{Time}}}}\]
Here we have found a new term which is called the displacement. Displacement is defined as the shortest distance between two points and also, we consider the direction of the movement. If a substance starts and ends its movement at the same point, then the value of displacement will be zero and the value of velocity will be also zero. But in the same case, the distance travelled by the object will not be zero and if we can calculate that, we can know the speed of the object. Thus, velocity is the property of a moving object when its speed is said along with the direction in which it moves.

So, the correct answer is Option A.

Additional Information:
As the displacement is the shortest distance between two points, it will always be a straight line. Distance and displacement will be the same for objects moving in a straight line.

Note: An object in space is marked by its position at a particular time. If its position changes uniformly with change in time, then we can say that it is in uniform motion. Speed only tells about how fast it is fast but the velocity tells exactly about their direction along with speed.