NIOS Class 10 Science Gravitation Activity 11.3 Explanation

This activity demonstrates how air resistance affects the falling objects. We have already learnt that masses of objects do not affect the speed of free-falling objects in activity 11.2.

 

NIOS Class 10 Science and Technology (212) Project File

This activity is based on the NIOS Class 10 science and technology (212) Chapter 11- Gravitation, Module 3- Moving Things.

Effect of Air Resistance on Falling Objects

Aim

To observe the effect of air resistance on the fall of objects

Materials Required

   1.  On a 5 Rupee coin

   2.  A square sheet of paper

 

   Procedure

  We take a five-rupee coin and a sheet of square paper. Now we drop them at the same time from the same height and observe which one reaches the ground first.

 

Now we crumple the same sheet of paper into a small ball. We drop the same coin and the ball of paper at the same time and same height and observe which one reaches the ground.

Observation

We observe:

   1.  In the first case, the coin reaches the ground before the paper.

   2. In the second case, both the coin and the crumpled paper ball reach the ground at the same time

Explanation

First case

The flat paper sheet has a large surface area, so it experiences greater air resistance, but on the other hand coin has a small surface area, so it experiences less air resistance. That’s why the coin reaches the ground faster than the flat sheet of paper.

Second case

The surface area of the paper sheet reduces after crumpling and experiences less air resistance than the coin experiences, so both reach the ground at the same time.

Conclusion

This activity explains that air resistance can slow the fall of objects with a large surface area. In negligible air resistance, all objects experience the same acceleration due to gravity.

Frequently Asked Questions

   1.  Why did the flat paper fall more slowly than the coin?

Answer – Because flat paper has a larger surface area than a coin, it experiences greater air resistance.

   2. Why did the crumpled paper and the coin fall at the same speed?

Answer – Because crumpled paper has reduced surface area

   3. What would happen if there were no air or a vacuum?

Answer - In the absence of air (vacuum), objects of different masses will fall with the same speed.