To determine which of the given quantities is a vector quantity, we need to understand the difference between vector and scalar quantities.
Vector Quantity:
- A vector quantity is defined by both its magnitude and direction. Examples include velocity, force, and acceleration.
Scalar Quantity:
- A scalar quantity is defined only by its magnitude. Examples include mass, speed, and volume.
Let's analyze each of the given quantities:
- Acceleration (Choice A):
Acceleration describes the rate of change of velocity. It has both magnitude (how much the velocity changes) and direction (the direction in which the velocity changes). Therefore, acceleration is a vector quantity.
- Mass (Choice B):
Mass is a measure of the amount of matter in an object. It only has magnitude and no direction. Therefore, mass is a scalar quantity.
- Speed (Choice C):
Speed is the rate at which an object covers distance. It only has magnitude (how fast something is moving) and no direction. Therefore, speed is a scalar quantity.
- Volume (Choice D):
Volume is the amount of space occupied by an object. It only has magnitude and no direction. Therefore, volume is a scalar quantity.
Given this analysis, the correct answer is:
[tex]\[ \boxed{\text{A. acceleration}} \][/tex]
