4. Like ve lo c ity & a c c e le ra tio n ,
Fo rc e s have both magnitude
and direction.
5. TYPES OF FORCES
INTERNAL FORCE
EXTERNAL FORCE
BALANCED FORCE
UNBALANCED FORCE
6. INTERNAL FORCE
An internal force is a force acted
upon by an object to force another
object’s movement internally.
Internal force include gravity
forces, magnetic force, electrical
forces and spring forces.
7. EXTERNAL FORCE
An external force is a force exerted
upon an object based on the object’s
position.
External forces include the applied
force, normal force, tension force,
friction force and air resistance
force.
8. EXAMPLES
A baseball.
Internal force: The forces holding the particles of the baseball
together.
External force: The force of a bat hitting the ball on the ball; so is
gravity
A car.
Internal force: The parts of the car exert forces on each other : the
pistons push the rods , the axle pushes the wheels , etc. are
internal forcesto the car as a whole.
External force :The friction that the ground exerts on the tyres , the
weight of the car , and the force the group exerts to hold up the
car.
9. Balanced force
Opposite and equal forces acting on the
same object results in no motion of the
object.
10. Unbalanced force
Two or more forces of unequal strength
or direction acting upon an object
results in the motion of the object.
11. Newton’s first law of motion
“ Any body continues to be in a state of
rest or of uniform motion in a straight
line until an unbalanced external force
is applied on it ”
