Answer in detail

Question

If a particle is moving along a straight line with increasing speed, then 

(1) Its acceleration is negative 

(2) Its acceleration may be decreasing 

(3) Its acceleration is positive

(4) Both (2) & (3)

Answer 1

Answer: (4) Both (2) & (3)

If a particle is moving along a straight line with increasing speed then its acceleration is positive The reason for its acceleration being positive is because the velocity with which it is moving is positive. When a body is moving in a straight line with increasing speed, then it signifies that the velocity in result is also increasing with constantly.

In option (2) it contains the word 'may' so the statement only needs to be true sometimes. It is true, for example, when a particle moves right with increasing speed due to a force acting to the right, even though the magnitude of of the force is decreasing. The decreasing force decreases the acceleration, but the acceleration is still positive and causes speed to increase.

Comments

Thanks for the answer. But in my opinion option 2 is correct because in the ques., speed is asked and not velocity. And speed doesn't depend on direction. What do you say??