Forces

1. BALANCED FORCE
and
UNBALANCED
FORCE
FATIMA D. BALUNSAT

2. Magnitude
• Refers to the size or
the strength of force

3. Balance Force
• If two individual forces
acting on an object are
equal in magnitude and
in opposite direction.

4. • Balance forces cause an
object to be at rest at a
constant speed with zero
acceleration.

5. Examples
• A book resting on a table.
F
n
W
FfFa

6. • Fn (normal force) and W (weight) cancel each
other out as they are of equal magnitude but
act in the opposite direction.
• Fa and Ff cancel each other out as they are of
equal magnitude but act in the opposite
direction.
• The forces acting on the book are balanced.
• The book remains at rest.

7. II. An object moving on a
horizontal surface.
Constant speed
Object F
f
Fa

8. • Fa and Ff cancel each other out as they are of
equal magnitude but act in the opposite
direction.
• The forces acting on the object are balanced.
• It will continue to move at constant speed.
• The acceleration of the object is zero.

9. UNBALANCED FORCE
• An object is said to experienced an
unbalanced force when a force acting
on the object is not balanced by
another force of equal magnitude but in
opposite direction.
• Unbalanced forces cause an object to
accelerate.

10. Examples
• An object accelerates downwardly.
Smaller Fn
Accelerates downwards
in the direction of W
Greater W

11. • Fn W
• Fa and W do not cancel each other out as
they are not equal.
• The forces acting on the book are not
balanced.
• The objects will accelerate in the direction
of W.

12. II. An object accelerates on
a horizotal surface.
Object
moving with the acceleration
in the direction of Fa
greater Fa
Smaller Ff

13. • Ff is less than Fa.
• Ff and Fa do not cancel each other as they
are not equal.
• The forces acting on the book are not
balanced.
• The object will accelerate in the direction
of Fa.

14. Reference
• Tan Ming Eng, (2017 Reprint)“Conceptual
Learning Physics 3rd Ed..GLM Pte. Ltd.
Singapore

15. • THANK YOU!