Question

Which of the following doesn’t belong to a group?
A) Velocity
B) Acceleration
C) Speed
D) Displacement

Answer 1

Hint: If the options are observed , we can analyze that these are some of the basic physical quantities. It is known to us that all physical quantities can be grouped into two categories, scalar quantities and vector quantities. So, we have to define all these quantities and find out whether they are vector or scalar.

Complete answer:
The scalar quantities are those quantities that only require magnitude to specify them completely. On the other hand, a vector quantity is a physical quantity that specifies both magnitudes as well as direction.
Now, let us consider velocity which can be defined as the displacement covered by a body in a unit of time. It gives the magnitude as well as the direction in which the object is moving. Thus, it is a vector quantity.
Similarly, acceleration is defined as the rate of change of velocity. As velocity is a vector quantity, therefore acceleration is also a vector quantity.
Displacement is defined as the measurement of the length of the shortest path covered by an object from the initial point to the final point. It also mentions the direction and hence a vector quantity.
On the other hand, speed is referred to as the distance covered per unit time. It only gives the magnitude and contains no information about the direction of the object. Hence, speed is a scalar quantity.
Therefore, option (C) doesn’t belong to the group.

Note: Scalar quantities can never be negative but vector quantities can be negative, positive or zero. When the object is moving in a circular path, then the displacement of the object after completing one rotation will be zero as the initial and final points coincide with each other.