Question

Explain when will the value of acceleration be zero,positive or negative​

Answer 1

Answer:

Positive acceleration means acceleration in the direction of velocity ( it always increases the speed of particle).

●Negative acceleration means acceleration opposite to the direction of velocity ,it is also known as retardation (it always decreases the speed of the particle).

●Zero acceleration means body is not accelerating, in this case it's velocity is constant .The body moves in a straight line, it neither speed up or down nor change direction .

【 In vector form , if angle between velocity vector and acceleration vector is less than 90° and greater than 0° then it is positive acceleration and if it is less than 180° and greater than 90° then it is negative acceleration. If there is no acceleration vector then it is called zero acceleration. 】

【 If dot product of acceleration vector and velocity vector is positive then positive acceleration and if dot product of acceleration vector and velocity vector is negative then acceleration is negative.

◆If dot product is zero then it will be either zero acceleration or angle between acceleration vector and velocity vector is 90° ( in this case acceleration is going on but here speed is not changing rather only direction of particle is changing)】

hope this will help you