Question

Under the action of a constant force, a particle is experiencing a constant acceleration. The power is?
(A) Zero
(B) Positive Constant
(C) Negative Constant
(D) Decreasing uniformly with time.

Answer 1

We are given a situation where a constant force is applied on a particle and is experiencing a constant acceleration and are asked to find the power of the particle. Thus, we will use the formula for power of a particle.
Formulae Used:
$P = F.v = F.at$
Where,$P$ is the power of the particle,$F$ is the force on the particle, $v$ is the velocity of the particle, $a$ is the acceleration of the particle and $t$ is the time of the particle under the force.

Complete step by step answer:
Here,
We are given that the particle is under a constant force and is experiencing a constant acceleration.
Let us assume that the constant force is$F$ and the experienced acceleration is$a$.
Now,
The power of the particle,$P = F.at$
Now,
$F$ and $a$ are constant
Thus, The power increases continuously with respect to time.
For a specific time, the power is a positive constant.

Hence, The correct option is (B).

Additional Information: The power of a body is defined as the rate of change of energy. Now, the energy can be formulated as the product of force and displacement of the body. Now, if we make the rate of change of energy, we get that the power of a body is the product of force and velocity of the body.

Note: We evaluated the power to be a positive constant for a specified amount of time. But if the situation was of a retarding force, then the answer would have been a negative constant.