REVATHY R NATHAN WELCOME Physical Science
REVATHY R NATHAN
WELCOMEPhysical Science
SABARIGIRI COLLEGE OF EDUCATION
FORCE AND PRESSURE
FORCE
INTRODUCTION
EFFECTS OF FORCE
FRICTION
RELATIONSHIP BETWEEN FORCE AND PRESSURE
FORCE IS A PUSH OR PULL OR BOTH
A force to move an object away from our bodies
A pull is when we apply a force to move an object
towards our body
PUSH PULL
Launching Rocket Pulling
a box
COMBINATION OF PUSH AND PULL
Playing a guitar
Sawing wood Scrubbing the floor
Rowing a boat
EFECT OF
FORCE
CHANGES THE SHAPE TEMPORARILYCHANGES THE SHAPE PERMANENTLYCHANGES THE DIRECTION OF A MOVING OBJECTCHANGES THE SPEED OF A MOVING OBJECTSTOPS A MOVING OBJECT OR MAKES A STATIONARY OBJECT MOVES
CHILDREN’S MISCONCEPTION
A SOLID CANNOT BE COMPRESSED OR STRETCHED
EXPLANATION
THE SHAPE OF A SOLID OBJECT CHANGES WHEN A FORCE IS APPLIED TO IT WHETHER IT’S TEMPORARIRLY OR
PERMANENTLY EXAMPLE : CRUSHING A CAN
(CHANGES THE SHAPE PERMANENTLY)
WHEN A FORCE IS APPLIED
IN AN OPPOSITE
DIRECTION (DIFFERENT
DIRECTION) THE APPLYING
OBJECT WILL CHANGE
THE MOVING DIRECTION
A STATIONARY BALL WILL MOVE WHEN IT IS KICKED
THE MOVING BALL WILL STOP WHEN AN EQUAL FORCE IS APPLIED IN THE OPPOSITE DIRECTION OF ITS MOTION
MOVES IN THE SAME DIRECTION AS IS THE APPLIED FORCE
FORCE IS A PROPERTY OF AN OBJECT. AN OBJECT HAS FORCE WHEN IT RUNS OUT OF FORCE IT STOPS MOVING
EXPLANATION
AN OBJECT AT REST OR IN MOTION WILL
REMAIN IN THAT STATE UNLESS AN EXTERNAL FORCE IS APPLIED TO
THE OBJECT
NEWTON 1ST LAW
FRICTIONOCCURES WHEN TWO SURFACES ARE MOVING
IN CONTACT WITH EACH OTHER
FACTORS THAT EFFECT FRICTION:
Physical condition of the surface Weight of an object
WAYS TO REDUCE:
Use ball bearing Use wheel and axle
FRICTIONADVANTAGES: Enables people to run and work without falling or slipping
Enables us to write on paper
Enables a car to stop when the brakes are applied
DISADVANTAGES:
Slow down a moving object
Causes the surfaces of objects to wear out Causes less effectiveness of moving machine
EXAMPLES OF FRICTION
RELATIONSHIP BETWEEN FORCE AND PRESSURE
AIR PRESSURE
PULL AND PUSH
APPLYING FORCE
A FORCE IS APPLIED TO THE PUMP TO PRODUCE AIR PRESSURE
THANKS