A body executing non-uniform motion: A. undergoes acceleration B. never undergoes acceleration C. may or may not undergo acceleration D. never undergoes constant acceleration
Hint: When a body is executing uniform motion, the velocity of the body will be constant i.e. the body will not undergo any change in velocity. When the body is executing non-uniform motion, the velocity of the body will change with time.
Complete answer: Non-uniform motion of a body can be defined as the motion of a body whose speed is changing with time. If the velocity of a body is changing with time, the body is accelerating. A non-accelerating body will have constant velocity and hence will undergo uniform motion. So, we can say that a body executing non-uniform motion undergoes acceleration. The velocity may increase or decrease with time for the non-uniform motion. So, we can get both positive and negative acceleration for a body in non-uniform motion. This acceleration may or may not be constant, because the rate of change of velocity of the body in non-uniform motion can be changing with time. But if the rate of change of the velocity of the body in non-uniform motion is constant, then the acceleration will be constant for the motion. So, we cannot say that the body will not undergo constant acceleration.
So, the correct answer is “Option A”.
Note: When we draw a velocity time graph for body executing uniform motion, we will get a straight line parallel to the time axis. For position time graphs also, we will get a straight line. If we draw a velocity time graph for the body executing non-uniform motion, we will not get any straight line.