FORM 2-PHYSICS-TOPIC 7-NEWTON'S LAW OF MOTION
Difference between Action and Reaction Forces
Distinguish between Action and Reaction Forces
Consider a book of mass, m which is at rest on a table. This book will exert on a table with a force equal to its weight. The table exert an equal upward force.
The downward force exerted by the book(weight) on the table is known as action force while the upward force exerted by the table on the book is known as reaction force.
These two forces acts in opposite direction but they are equal in magnitude.
Where; R = reaction, mg=weight of a book
Newton's Third Law of Motion
State Newton's third Law of Motion
Newton’s 3rdlaw of motionstates that “To every action there is an equal and opposite reaction”
Application of Newton's Third Law of Motion
Apply Newton's third Law of Motion
The person firing a gun will feel the recoil when the bullet leaves the gun.
Consider a gun of mass mg ejects a bullet of mass mb with a velocity vb and the gun recoils with velocity vg.
From the principle of conservation of momentum:
Recoil momentum of gun = Momentum of bullet
mgvg =mьvь
