| | Newton's Laws of motion | | Isaac Newton was one of the greatest scientists that ever lived.During his lifetime,he propounded laws of motion which later became known as the Newton's laws of motion | | | Newton's laws of motion can be stated as follows:
- A body continues in its state of rest or of uniform motion in a straight line unless it is acted upon by an external or impressed force
- The rate of change of momentum of a body is directly proportional to the applied force.
- To every action,there is always an equal but opposite reaction.
| | | | Now,we shall take each of these laws and explain them in turn.What Isaac Newton was trying to explain by the first law of motion is that if you have a solid object e.g. a chair and is allowed to remain in a place for a time,it continues to remain in that place as long as nobody touches it or moves it.But if it is moved,you find it no more there,but somewhere else,and that this can only be caused by an external force or impressed force.In other words,your chair would not move itself except somebody else moves it,and similarly,it would not stop moving immediately it starts except somebody stops it.An example can be seen in a free falling object .Immediately,it starts to fall,it continues to fall,until it is stopped by an external object or force.Similarly,immediately it starts to remain at rest,it continues to remain at rest. | | | | The second law of motion speaks of the relationships between the rate of change of momentum and the applied force.As the applied force increases,the rate of change of momentum also increases.Force produces acceleration,and as the forces acting on a body remain equal to zero,the body ceases to accelerate,but moves with a constant or uniform velocity.When this situation arises,the velocity experienced is called Terminal velocity. | | | The third law of motion explains what we experience everyday of our life.When you sit on a chair,you experience it,and when a body is placed on a floor,it also experiences it.The action exerted by the body on the ground is equal and opposite to the reaction of the ground on the body.This is the third law of motion.The second law of motion can be mathematically expressed as follows:
F=m(v-u)/t
F=mv-mu/t
Ft=mv-mu
where Ft=impulse
mv-mu=Change of momentum
F=m(v-u)x1/t
F is directly proportional to m(v-u)=1/t
Where 1/t is the constant of proportionality. | | | | | | | | | | | | | | |
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