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So up until this point, we were busy mostly with kinematics, that is things that involve the position,

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the speed and acceleration of a particle.

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But we considered this particle to be massless.

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We did not consider the forces that might work in on this particle and that is called kinematics.

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What are we going to look at going forward is kinetics and kinetics looks at the causes of motion that

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will say that the particle that undergoes position, speed and acceleration has a certain mass which

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we are going to consider.

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We are going to consider certain forces that works on this mass and that is called also dynamics.

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And an example of kinematics that we have looked at in the previous videos is the study of celestial

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bodies, how planets move around the sun, for instance, how a moon moves around the planet.

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You can describe the motion of that body using kinematics without considering the fact that the body

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has a certain mass.

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So Chromatics is just describing the position mostly as a function of time.

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When you look at kinetics, you are going to incorporate the mass in the forces.

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So that is mostly employed where you design things like airplanes and motor vehicles, trains, etc.

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So they we need to consider how different forces work in on this body and for that we will use a free

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body diagram.

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So there are three methods of solving kinetics problems that we are going to look at.

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The first one is Newton's second law, which says that F is equal to M times A, the force is equal

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to the mass of the body multiplied by its acceleration.

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And that force you will see is the sum of forces working on the body broken down into different directions,

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you'll see.

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We'll do an example of that.

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So if is equal to M times a mass multiplied by acceleration, that's Newton's second law.

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That is a starting point for solving some kinetics problems.

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Another starting point for solving some kinetic problems is the principle of work and energy.

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We will look at that as well.

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And then we will also look at the principle of impulse and momentum.

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So without further ado, let us look at Newton's second law and how we can use that to solve a kinetic

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problem.