Question

How does air resistance affect the motion of an object?

Answer 1

Hint: In this question, we will use the direct formula of air resistance. From this formula we will easily get the required answer. We will also know about the friction force. Further, we will study about the different types of frictional force, for our better understanding.

Formula used:
$F_D={\displaystyle \frac{1}{2}}\rho v^2{C}_{D}A$

Complete answer:
As we know that frictional force opposes the motion of an object or body. Similarly, air resistance acts the same like the frictional force; they impart a force that points in the opposite direction of the object's motion.

So, we can say that when an object is not moving there is no air resistance or frictional force present.

Also, we have the air resistance formula, which is given as:
$F_D={\displaystyle \frac{1}{2}}\rho v^2{C}_{D}A$
Here,
$F_D$ is the drag force
$\rho$ is the density of the fluid
v is the velocity or speed of the object relative to fluid
$C_D$ is the drag coefficient
and the last term A is the cross-sectional area

So, we can say from the above formula that the higher the velocity of the object, the more air resistance will be for that object.
Therefore, we get the required answer.

Additional information:
As we know that the friction force can be defined as the force exerted by a surface when an object moves across it or even makes an effort to move across the surface. There are three types of friction force - sliding friction, rolling friction and static friction. It can be said that the friction force often opposes the motion of an object.
Static friction comes into action on objects when they are resting on a surface. Without this friction, our feet would slip out and thereby, making it difficult to walk.
Sliding friction is friction that comes in action on objects when they are sliding over another surface. As we know that the sliding friction is weaker than the static friction.
The last one is rolling friction is friction that comes in action on objects when they are rolling over another surface. Rolling friction is much weaker than sliding friction and static friction.

Note:
Frictional force is a force that opposes the motion of any object. There are many practical examples of frictional force. We should also remember that various kinds of lubricants are used to overcome the frictional force like- grease, oil etc.