Question

Which of the following is/are true about acceleration?
A. Acceleration is defined as the rate of change of velocity with respect to time.
B. Its SI unit is\[{\text{m/}}{{\text{s}}^{\text{2}}}\].
C. Negative acceleration is called retardation.
D. All of the above.

Answer 1

Hint: Acceleration is a quantity of vectors which measures the rate for which an object increases its velocity. An object accelerates as its velocity is increasing. Retardation is the decrease of acceleration.


Complete step by step solution:
In mechanics, acceleration is the rate of change of an object's velocity as regards time. Accelerations are quantities of the vectors (in that they will be of magnitude and direction). The acceleration orientation of an object is given by the orientation of the net force acting upon the object. The magnitude of the acceleration is given at any point on a trajectory by the rate of velocity change at that point, in both magnitude and direction.

Acceleration has the velocity \[\left( {L/T} \right)\] dimensions separated by the distance, i.e. \[{\text{L}}{{\text{T}}^{{\text{ - 2}}}}\]. The SI unit of the acceleration is the metre per second squared\[\left( {{\text{m}}{{\text{s}}^{{\text{ - 2}}}}} \right)\]; as the acceleration value varies per second by the velocity in metres per second.

Retardation is like an acceleration of negative effect. The body's momentum will either go up or down. The velocity shift is called acceleration. If the body's velocity increases it is said that acceleration is positive. Similarly the amplitude is assumed to be negative if the velocity reduces. If a car is about to break it slows down. We may assume the car is retarding in this situation. Retardation is a negative indicator of acceleration. Or the negative acceleration value means a body's velocity is decreasing.

Hence, option D is correct.

Note:In this question the option D is correct as it stands for all the true aspects of acceleration. This means, acceleration is the rate of change of an object’s velocity as regards time. The SI unit of the acceleration is the metre per second squared \[\left( {{\text{m}}{{\text{s}}^{{\text{ - 2}}}}} \right)\], and retardation is a negative indicator of acceleration.