Question

The speed of a particle moving along a straight line increases as time passes and the acceleration is negative. This situation is not possible in practice.

• A. True
• B. False

Answer 1

The correct option is B False

Acceleration:

1. The rate of change of velocity with respect to time.
2. It is a vector quantity.

Deceleration:

1. Deceleration of a body whose velocity is decreasing with time.
2. For the deceleration of a body, the direction of velocity and acceleration is always opposite in direction.

When a particle moves along a straight line:

1. The first equation of motion is $v=u+at$. Here, $v$ is the velocity of the particle, $u$ is the initial velocity of the particle, $t$ is the instant at which velocity is being calculated and $a$ is the acceleration of the particle at this instant.
2. If we keep acceleration as negative in $v=u+at$ then the velocity will decrease for sure.
3. Thus, when a velocity is positive as well as increasing then its acceleration can be decreasing but velocity should be positive.
4. Therefore, the given situation is not possible in practice.

Hence, the given statement is false.