Newtons third law of motion

Newtons third law of motionChapter 2 force and motionNewtons third law of motionWhen you are practising arm wrestling with your friend, you will feel a force acting on you.Your friend will also be feeling a force acting on him.This is because while he is applying a force on you, you are also applying a force on him.

Newtons third law of motionIf object A exerts a force, F on object B, the object B will exert an equal but opposite force, - F on object A. This law is also known as the action reaction law. Hence, Newtons third law of motion can be quoted asTo every action, there is an equal but opposite reaction.

Everyday phenomena that are governed by newtons third law of motion:

A swimmer pushes the water backward with his hands and legs with a force, F, while the reaction force of water, F, pushes the swimmer forward.

When a boy presses on the wall with a force, F, the wall presses on his hand with a normal reaction force, F.

When a man paddles with a backward force, + F (action), the reaction force, F, pushes the boat forwards.

The principle used in rockets and jet engines can be also be explained by newtons third law of motion. The action that pushes the exhaust gases out through the nozzle results in a forward force (reaction forces) that propels the rocket or jet engine forwards.Summary of newtons law of motionNewtons First Law of MotionEvery object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.This is often termed simply the "Law of Inertia"

Summary of newtons law of motionNewtons Second Law of MotionThe relationship between an object's mass, m, its acceleration, a, and the applied force, F is F = ma.In this law the direction of the force vector is the same as the direction of the acceleration vector.

Summary of newtons law of motionNewtons Third Law of MotionFor every action there is an equal and opposite reaction.ExerciseA force of 10 N acts on a 2 kg stationary object. Calculate the distance travelled by the object in 5 s.

An object with a mass of 5 kg moves at a constant velocity when it is pulled by a horizontal force of 5 N on a level surface. What is the acceleration of the object if pulled with a force of 25 N

Puan Zaitun pushes a trolley of mass m kg with a force of 30 N. The trolley moves with a uniform velocity of 1 ms-1. When she doubles her force, the trolley accelerates at 2 ms-2. Find the mass of the trolley.