Summary Grade 12 IEB Physical Science: Newton's Laws and Application of Newton's Laws

NEWTON’S LAWS AND
APPLICATION OF NEWTON
LAWS




@STUDYNOTESBYM

,1. DIFFERENT KINDS OF FORCES: WEIGHT, NORMAL FORCE,
FRICTIONAL FORCE, APPLIED (PUSH, PULL) FORCE, TENSION
(STRING OR CABLES)

WEIGHT
The gravitational force that the earth exerts on any object on or near its surface


𝐹𝑔 = 𝑚𝑔
𝐹𝑔: 𝑡ℎ𝑒 𝑓𝑜𝑟𝑐𝑒 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 𝑖𝑛 𝑁
𝑚: 𝑚𝑎𝑠𝑠 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 𝑖𝑛 𝑘𝑔
𝑔: 𝑔𝑟𝑎𝑣𝑖𝑡𝑎𝑡𝑖𝑜𝑛𝑎𝑙 𝑎𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛 = 9,8 𝑚. 𝑠 −2




NORMAL FORCE

The perpendicular force exerted by a surface on an object in contact with it




FRICTIONAL FORCE

The force that opposes motion of an object and acts parallel to the surface with which the
object is in contact



• The force opposes motion
• Acts parallel to the surface
• Acts opposite to the direction of movement
• It never causes movement
• Can never be greater than the applied force

, STATIC FRICTION VS KINETIC FRICTION

STATIC FRICTION KINETIC FRICTION
Frictional force that acts on an object Frictional force that acts on object that is
while it is at rest moving
• Varies from minimum to maximum • Object moves as the force of friction
• In the case of static friction, the has been overcome by the applied
applied force has not yet overcome force
the frictional force

𝐹𝑠 𝑚𝑎𝑥 = 𝜇𝑠 𝐹𝑁 𝐹𝑓𝑘 = 𝜇𝑘 𝐹𝑁




PUSH AND PULL APPLIED FORCES

• Push and pull forces are applied forces
• Push and pull forces act in opposite
directions to one another
• Push forces act on the object
• Pull forces act away from the object




FORCES APPLIED AT AN ANGLE

• Push and pull forces applied at an angle can be deduced into a vertical and
horizontal component

PUSH FORCE AT AN ANGLE PULL FORCE AT AN ANGLE