Question

After terminal velocity is reached, the acceleration of a body falling through a fluid is:
$\left(A\right)$ Equal to g
$\left(B\right)$ Zero
$\left(C\right)$ Less than g
$\left(D\right)$ Greater than g
$\left(F\right)$ Constant but not zero

Answer 1

Hint: Terminal velocity can be achieved by an object freely falling through a liquid or gas. It is the highest velocity attained by freely falling objects through a liquid or gas. The body after attaining terminal velocity will continue to move with the same velocity. Using the above statement determines the acceleration of a body falling through a fluid.

Complete answer:
Terminal velocity is the highest velocity attained by freely falling objects through a liquid or gas. Terminal velocity tends to get confusing because they depend on whether or not a body is in empty space or in a fluid. The downward force of gravity is equal to the sum of the object’s buoyancy and the drag force when terminal velocity is reached.
The net acceleration of the body falling through a fluid or gas is zero, after terminal velocity is reached because the body after attaining terminal velocity will continue to move with same velocity. When an object is dropped from rest, its speed will increase until it reaches the terminal velocity and upon reaching the terminal velocity speed slows down and the velocity will become constant.
Once the terminal velocity is reached, the net acceleration of the body falling through a fluid is zero. The body after attaining terminal velocity will continue to move with the same velocity. Once the terminal velocity is attained then the velocity will become constant. We can say the acceleration of the body will become zero.

Hence the option $B$ is the right option.

Note: At terminal velocity the object has zero net acceleration. The body after attaining terminal velocity will continue to move with the same velocity. Once the terminal velocity is attained then the velocity will become constant. Then acceleration of the body will become zero. Terminal velocity can be achieved by an object freely falling through a liquid or gas.