Physics Knowledge

Chapter-3-Physics
Newton's 2nd Law
The resultant forces acting upon an object is
equal to the product of the mass and the
acceleration of the object.
F=ma
SI unit for force: newton (N)
1N = 1kg m s^2
The direction of the force is the same as the
object's acceleration
The direction of the free body is dependent on
the resultant force
Resultant Force
A resultant force would cause...
A moving object to...
A stationary object to move
Stop
Increase speed
Decrease speed
Change direction
Deform
It can be calculated by addition or subtraction for parallel forces.
Friction
Bad effects
Creates Heat
Causes wear and tear
Wastes energy
Good effects
Prevents slip
Reducing friction
Moving parts made smooth
Materials with low friction resistance
Use lubricants
Use air cushion
Depends on
Material type
Roughness
is proportional to the force pressing surfaces
together
1kg = 10N
Newton's 1st Law
1) An object at rest would remain at rest
2) An object in motion will continue to be in
motion at a constant speed in a straight line
3) In the absence of a resulting
force acting on it
In this law, the forces are balanced
For example...
A rock on a table
The rock's weight is
pushing down on the table
The table's reaction force
pushes it back (3rd law)
Freefall
A falling object would reach a point where
Air resistance = Weight
This is called terminal velocity
Resultant Force = 0N
No resultant force ≠ No force
All force are balanced
Newton's 3rd Law
For every action there is an
equal and opposite reaction
Action and reaction act on different objects
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