INTRODUCTION TO PHYSICS

[Audio] Hi everyone Today we have collection of topics About the introduction of physics.

[Audio] These topic includes Relation between distance and displacement Difference between speed and velocity Acceleration Scalars and vectors Definition of force Newton laws of motion Force of friction Types of frictions Gravitational force Centripetal force Definition of energy and its types Momentum And torque.

[Audio] DISTANCE LENGTH OF PATH BETWEEN TWO POINTS IS CALLED DISTANCE. IT IS A SCALAR QUANTITY. IT CAN BE REPRESENTED BY S. ITS SI UNIT IS METER FOR EXAMPLE DISTANCE BETWEEN TWO CITIES BY ROAD DISPLACEMENT SHORTEST DISTANCE BETWEEN TWO POINTS IS CALLED DISPLACEMENT. IT IS A VECTOR QUANTITY. IT CAN BE REPRESENTED BY d. ITS SI UNIT IS METER DISTANCE BETWEEN TWO CITIES BY AIR ARE EXAMPLE OF DISPLACEMENT..

[Audio] SPEED DISTANCE TRAVELLED IN UNIT TIME IS KNOWN AS SPEED. IT IS A SCALAR QUANTITY. MATHEMATICALLY, SPEED EQUAL TO DISTANCE BY TIME ITS SI UNIT IS METER PER SECOND VELOCITY THE RATE OF DISPLACEMENT OF BODY IS CALLED VELOCITY. IT IS A VECTOR QUANTITY. MATHEMATICALLY, VELOCITY EQUAL TO DISPLACEMENT BY TIME ITS SI UNIT IS METER PER SECOND.

[Audio] ACCELERATION: THE RATE OF CHANGE OF VELOCITY OF THE BODY IS CALLED ACCELERATION. IT IS A VECTOR QUANTITY. IT CAN BE REPRESENTED BY a. MATHEMATICALLY A EQUAL TO V F MINUS V I DIVIDED BY TIME ITS SI UNIT IS METER PER SECOND SQUARE POSITIVE ACCELERATION: IF THE VELOCITY OF THE BODY INCREASE WITH TIME ACCELERATION IS POSITIVE. NEGATIVE ACCELERATION: IF VELOCITY OF BODY DECREASE WITH TIME ACCELERATION IS NEGATIVE. NEGATIVE ACCELERATION IS ALSO CALLED RETARDATION..

[Audio] SCALARS A SCALAR QUANTITY IS DESCRIBED COMPLETELY BY ITS MAGNITUDE ONLY. THE QUANTITY CHANGE WITH CHANGE IN MAGNITUDE. NORMAL RULES OF ALGEBRA ARE APPLICABLE. SPEED, WORK, TIME, DISTANCE ARE EXAMPLES OF SCALAR. VECTORS THOSE QUANTITIES WHICH HAVE BOTH MAGNITUDE AND DIRECTION ARE CALLED VECTORS. THE QUANTITY CHANGE WITH CHANGE IN MAGNITUDE & DIRECTION. VECTOR HEAD TO TAIL RULE ARE APPLICABLE. VELOCITY, ACCELERATION, FORCE ARE EXAMPLES OF VECTOR..

[Audio] FORCE: FORCE IS THE AGENCY THAT CHANGES OR TENDS TO CHANGE THE STATE OF REST OR OF MOTION. A FORCE MOVES OR TENDS TO MOVE STOPS OR TENDS TO STOP THE MOTION OF OBJECT FORCE CAN ALSO CHANGE THE DIRECTION OF MOTION. IT IS A SCALAR QUANTITY. ITS SI UNIT IS NEWTON MATHEMATICALLY, F EQUAL TO M A.

[Audio] NEWTON FIRST LAW OF MOTION: A BODY CONTINUOUS IN ITS STATE OF REST OR OF UNIFORM MOTION IN A STRAIGHT LINE PROVIDED NO NET FORCE ACTING ON IT. FIRST LAW OF MOTION IS ALSO KNOWN AS LAW OF INERTIA. LAW OF INERTIA: INERTIA OF THE BODY IS THE PROPERTY DUE TO WHICH IT RESISTS ANY CHANGE IN ITS STATE OF REST OR OF MOTION..

[Audio] NEWTON SECOND LAW OF MOTION: WHEN A NET FORCE ACT ON BODY IT PRODUCE ACCELERATION ON BODY IN THE DIRECTION OF APPLIED FORCE. THE MAGNITUDE OF ACCELERATION IS DIRECTLY PROPORTIONAL TO APPLIED FORCE AND INVERSLY PROPORTIONAL TO ITS MASS. MATHEMATICALLY, A IS PROPORTIONAL TO F A IS PROPORTIONAL TO ONE BY M COMBINING EQUATIONS; A IS PROPORTIONAL TO F BY M AND F EQUAL TO M A.

[Audio] NEWTON THIRD LAW OF MOTION: TO EVERY ACTION, THERE IS ALWAYS AN EQUAL BUT OPPOSITE REACTION. ACTION AND REACTION FORCES ALWAYS ACT ON DIFFERENT BODIES. FOR EXAMPLE: CONSIDER A BOOK LYING ON TABLE THE WEIGHT OF BOOK ACTING ON DOWNWARD DIRECTION. THIS IS THE ACTION. THE REACTION FORCE OF TABLE ACTING ON BODY IN UPWARD DIRECTION. SIMILARLY UPTHRUST OF BALLOON AND ROCKET PROPULSION ARE ALSO EXAMPLES OF THIRD LAW OF MOTION.

[Audio] FRICTION: A FORCE THAT OPPOSES THE MOTION OF MOVING OBJECT IS CALLED FRICTION. STATIC FRICTION: WHEN THE BODY IS AT REST, THE FRICTION IS SAID TO BE STATIC FRICTION. DYNAMIC FRICTION: WHEN THE BODY IS MOVING, THE FRICTION IS SAID TO BE DYNAMIC OR KINETIC FRICTION..

[Audio] GRAVITATIONAL FORCE: THE ATTRACTIVE FORCE BETWEEN TWO MASSES IS DIRECTLY PROPORTIONAL TO THE PRODUCT OF MAGNITUDE OF THEIR MASSES AND INVERSLY PROPORTIONAL TO SQUARE OF DISTANCE BETWEEN THEIR CENTRES. MATHEMATICALLY, F EQUAL TO G M ONE M TWO BY D SQUARE WHERE G IS GRAVITATIONAL CONSTANT ITS VALUE IS 6.67 MULTIPLY 10 RAISED POWER MINUS ELEVEN NEWTON METER SQUARE PER KG SQUARE THE VALUE OF G IS VERY SMALL HENCE WE DO NOT FEEL FORCE OF GRAVITATION..

[Audio] CENTRIPETAL FORCE: THE FORCE WHICH COMPELS THE BODY TO MOVE IN A CIRCULAR PATH. THE FORCE REQUIRED TO MOVE AN OBJECT IN A CIRCULAR PATH IS CALLED CENTRIPETAL FORCE. MATHEMATICALLY, CENTRIPETAL FORCE EQUAL TO M V SQUARE BY R THE ACCELERATION PRODUCED DUE TO CENTRIPETAL FORCE IS CALLED CENTRIPETAL ACCELERATION.

[Audio] ENERGY: THE ABILITY OF BODY TO DO WORK IS CALLED ENERGY KINETIC ENERGY: ENERGY POSSESSED BY A BODY DUE TO ITS MOTION IS CALLED KINETIC ENERGY. MATHEMATICALLY, KINETIC ENERGY EQUAL TO HALF M V SQUARE POTENTIAL ENERGY: ENERGY POSSESSED BY A BODY DUE TO ITS POSITION IS CALLED POTENTIAL ENERGY. MATHEMATICALLY, POTENTIAL ENERGY EQUAL TO M G H.

[Audio] MOMENTUM: MOMENTUM CAN BE DEFINED AS QUANTITY OF MOTION OF BODY. THE PRODUCT OF MASS AND VELOCITY OF BODY IS CALLED MOMENTUM. MOMENTUM IS A SCALAR QUANTITY. MATHEMATICALLY, P EQUAL TO m v ITS UNIT is kilogram meter per second.

[Audio] TORQUE: TORQUE CAN BE DEFINED AS " TURNING EFFECT OF FORCE" TORQUE IS ANALOGOUS OF FORCE. TORQUE PEODUCE ANGULAR ACCELERATION ON BODY. IT IS A VECTOR QUANTITY. MATHEMATICALLY, torque equal to r cross f ITS SI UNIT is newton meter.

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