Physics · MOTION IN A STRAIGHT LINE
हिन्दीConsider the following statements regarding one-dimensional motion of a body: (A) A body with zero speed at an instant can have non-zero acceleration at that instant. (B) A body with zero speed at an instant can have non-zero velocity at that instant. (C) A body moving with constant speed in a straight line must have zero acceleration. (D) A body with positive acceleration must always be speeding up. Which of the above statements are correct?
Correct answer · Option 4
(A) and (C) only
Explanation
Statement (A) is correct (e.g. at highest point of vertical throw). Statement (B) is false as speed is magnitude of velocity. Statement (C) is correct (constant speed in straight line implies constant velocity, hence zero acceleration). Statement (D) is false (if velocity is negative and acceleration is positive, speed decreases).