Question

Which of the following quantities is not a vector?
A) Mass
B) Displacement
C) Weight
D) Acceleration

Answer 1

Hint
A quantity having both magnitude and direction is called a vector whereas scalar only has magnitude and it is independent of direction. We analyze all the options and choose the scalar quantity from those.

Complete step by step answer
Mass is a measure of quantity of a substance which is a magnitude and doesn't have any relation with direction, so mass is a scalar quantity. Displacement is the distance between initial and final position of the quantity. To determine displacement, we need magnitude as well as direction. As the direction gives us exact displacement. So, displacement is a vector quantity. Weight is a type of force which is the sum of its components from all directions. Force is a vector containing magnitude and displacement, so is weight. Since displacement is a vector quantity, velocity which is the rate of change of displacement is also a vector quantity. Similarly, acceleration which is the rate of change of velocity is also a vector quantity.
Hence option (A) is correct.

Note
Weight and mass are related, but they are not the same. Mass remains constant anywhere on any planet whereas weight changes when we move to different planets as acceleration due to gravity changes. Acceleration in a negative direction is called Deceleration.