# Air friction on a A4 paper ( Classical Mechanics )

• bob195
In summary, the problem is how to find the drag or friction on a page dropped from waist height with 20 sheets and no instruments allowed. The equation F=-cv, where c is the constant for air friction and v is the velocity, can be used but it is difficult without a stopwatch. The best approach would be to make estimates using c for friction and g for gravity. It may be possible to estimate an acceleration by looking at the system, but differentiation may be necessary. However, due to the lack of instruments, the best that can be done is a crude estimate. The paper will likely reach terminal velocity, where the weight is balanced by air resistance.
bob195

## Homework Statement

How could u find the drag/friction due to air on a A4 size page dropped perpendicular to the ground. There are about 20 sheets and is dropped about waist height. The tricky thing is no instruments are aloud. Only your senses...

## Homework Equations

F=-cv where c is the constant due to air friction. v is the vel and F the force of air

## The Attempt at a Solution

have no clue because i would think u would at least need a stop watch.

If you are given no instruments you will need to make estimates.

what estimates? u will have c for the friction and g for the gravity.u could considers some sort of acceleration from looking at the system.could it be done? i would think it would be of the function speed and maybe have to differentiate a few times but would not know where to start...

Because of the lack of instrument the best that can be done is a crude estimate.The falling paper tends to rock to and fro but there doesn't seem to be a net vertical acceleration.I think you are expected to assume it reaches terminal velocity this being when the weight of the paper is balanced by air resistance.

## 1. How does air friction affect the motion of an A4 paper?

Air friction, also known as air resistance, is a force that opposes the motion of an object through the air. As the A4 paper moves through the air, it experiences a force in the opposite direction of its motion due to air particles colliding with its surface. This force decreases the speed and changes the direction of the paper's motion.

## 2. What factors affect the amount of air friction on an A4 paper?

The amount of air friction on an A4 paper is affected by several factors, including the speed of the paper, the surface area and shape of the paper, and the density and viscosity of the air. As the speed of the paper increases, the force of air friction also increases. A larger surface area or an irregular shape of the paper will also result in a greater amount of air friction. Additionally, denser and more viscous air will produce more air friction.

## 3. How does the weight of the A4 paper impact air friction?

The weight of the A4 paper does not directly affect the amount of air friction it experiences. However, the weight does impact the acceleration of the paper due to air friction. Heavier papers will experience a greater force of air friction, which will result in a slower acceleration.

## 4. How can air friction be reduced on an A4 paper?

There are a few ways to reduce the effects of air friction on an A4 paper. One way is to decrease the speed of the paper, as the force of air friction is directly proportional to the speed of the object. Another way is to decrease the surface area of the paper by folding it or making it more streamlined. Additionally, using a smoother and less dense material for the paper can also reduce air friction.

## 5. How is air friction on an A4 paper related to other forces?

Air friction is an external force acting on the A4 paper, which is subject to other forces such as gravity and normal force. These forces can interact with each other and affect the motion of the paper. For example, the force of gravity pulling the paper down can counteract the force of air friction and result in a constant velocity for the paper. Additionally, the normal force exerted by a surface can also affect the amount of air friction experienced by the paper.

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