Understanding Conservative and Non Conservative Forces

Shuddhodan Sapre
20/04/2021 0 0

While teaching my students, I found them to fumble in this topic, so I am writing this lesson to tell you all in simple terms what the topic is:
Consider two cases in both cases; a block moves from A to B point and back.
Let's say a block is pushed from point A on a rough surface with a velocity V and the block goes to point B. While this is happening, let's say only frictional force acts on the block towards A. We can see that the block is being slowed down by friction, or in other words, the force is reducing the kinetic energy of the block. Now when this block reaches B, it stops, and friction stops acting. Now you need to think about where did the kinetic energy of the block GO?
Now take case 2; let's say the block has a spring attached, and now it is pushed from A to B but on a smooth surface with no friction. So only the spring force acts and pulls the block backwards towards A. So the spring force is reducing the speed of the block like friction is reducing the kinetic energy. The block reaches B and stops. At this moment, where did the kinetic energy GO?
If you compare both the cases and think about the kinetic energy disappearing, we find something interesting happening. We know that when we rub our palms, heat is produced because of friction. Similarly, in the first case, heat is produced, which might be very small in amount but is produced, and it is transferred on the block and on the floor, which eventually cools. The energy is dissipated or lost in the surrounding, never to come back. So the KE is lost in the form of heat due to friction. Hence the block stops since it has no more energy and cannot return to point A unless someone pushes it again.
If you consider the spring and what happens to the block after reaching point B, we see the block is pulled by the spring back towards A. This happens when the block stops just for an Instant. Now, where did the spring get the energy to pull the block? Wolla! It's the same Kinetic Energy that the block had. So as the block. Slowed down, its kinetic energy started to get stored in the molecular bonds of the spring in the form of elastic energy. And this energy was again given back to the block as kinetic energy. So you might be thinking, when the block reaches A, does it get all of its KE back, and the answer is Yes.
Such force like friction which removes energy and doesn't give it back is a Non-conservative force; as the name suggests, it doesn't Conserve the initial energy, but a force like spring force keeps on exchanging energy unless someone stops the block. Hence this force is called Conservative Force since it is conserving or not losing any energy.
You can apply the same logic of moving the block and checking the behaviour of the forces.
Now you try on the following forces:
1) Electrostatic Force.
2) Viscous Force.
3) Gravitational Force.
Conservative Force: 1,3.
Non-Conservative Force: 2.

0 Dislike
Follow 2

Please Enter a comment


Other Lessons for You

How to Solve Numericals in Physics?
Are you scared of numerical? Do you think you don't understand them? If yes, then read ahead. See, it might be any exam, but numerical won't leave your back. So let's talk about common problems and their...

Having trouble using Kinematic Equations?
How to use kinematic equations and when to use them? We all know the 3 kinematic equations which are S= ut + 1/2 at² V = u + at V²= u² + 2as Many students find it difficult to understand...

Trouble Understanding Friction?
Many of my students make a widespread mistake of taking friction value as f= μ N. Where μ = coefficient of friction and N =Normal Reaction. So is it incorrect? The answer is not exactly. With that,...

Looking to Learn?

Find best Tutors and Coaching Centers near you on UrbanPro.


Are you a Tutor or Training Institute?

Join UrbanPro Today to find students near you

Find Tutors, Trainers & Institutes near you

Post requirement and connect with the tutors in your locality

  • Select the best Tutor
  • Book & Attend a Free Demo
  • Pay and start Learning

Want to learn something New?

Find best tutors, trainers & institutes near you on UrbanPro

Post your learning requirement

This website uses cookies

We use cookies to improve user experience. Choose what cookies you allow us to use. You can read more about our Cookie Policy in our Privacy Policy

Accept All
Decline All

UrbanPro.com is India's largest network of most trusted tutors and institutes. Over 55 lakh students rely on UrbanPro.com, to fulfill their learning requirements across 1,000+ categories. Using UrbanPro.com, parents, and students can compare multiple Tutors and Institutes and choose the one that best suits their requirements. More than 7.5 lakh verified Tutors and Institutes are helping millions of students every day and growing their tutoring business on UrbanPro.com. Whether you are looking for a tutor to learn mathematics, a German language trainer to brush up your German language skills or an institute to upgrade your IT skills, we have got the best selection of Tutors and Training Institutes for you. Read more