In Grade 7, you described an object’s motion in terms of displacement, speed or velocity, and acceleration. You performed activities wherein you interpreted or created visual representations of the motion of objects such as tape charts and motion graphs. The concepts were arrived at by studying examples of uniform motion or objects moving in straight line at constant speed. Then you were also introduced to non-uniform motion where the object covers unequal distances or displacements at equal intervals of time. When a jeepney starts moving, it speeds up. When a jeepney nears a stop sign, it slows down. The jeepney is covering different displacements at equal time intervals and hence it is not moving at a uniform velocity. In other words, the jeepney is accelerating.

1. FORCES
PUSH OR PULL EXERTED BY
ONE BODY ON ANOTHER BODY;
THE EFFECT OF WHICH IS TO
TEND TO CHANGE OR CHANGE
THE STATE OF MOTION OF THE
BODY ON WHICH IT ACTS.

2. it is a vector quantity.
The SI unit of Force is Newton or N or we
can also have this expression 1kg
m/s2
Dyne= 1g cm/s2

3. REMEMBER!!!
Magnitude
refers to the size or strength of the
force. It is commonly expressed in
Newton (N)

5. FORCES CAN BE:
NON
FUNDAMENTAL
a.k.a Contact forces
Examples are:
Air resistance
Friction
Force applied when
punching someone

6. FUNDAMENTAL A.K.A
NON-CONTACT FORCES
Gravitational forces:
force of attraction
between object
Electromagnetic force:
either an attractive and
repulsive force

7. STRONG NUCLEAR FORCE
Holds the constituents of
the nucleus of an atom
together.
WEAK NUCLEAR FORCE
An role in the radioactive
decay of some nuclie.

8. objects remained
at rest because
the
forces acting on
them are equal in
magnitude and in
opposite
directions and
they lie
along the same
line of action
BALANCED
FORCE

9. Forces acting
on the objects
are no longer
equal in
magnitude
in opposing
sides.
UNBALANCED FORCE

10. combine or add forces to determine
the net or unbalanced force,
The algebraic signs + and – are used
to indicate the direction of forces.
Unlike signs
are used for forces acting in
opposite directions
COMBINATON FORCES

11. 1. During the activity, you and your classmate sare playing tug of
war your team has 500 N and the other team has 450N . What is
the net force? Which team will win?
Fnet = Fn + Fg
= 500 N + (-450 N)
= 50

12. If the sum of the forces equate to
zero, they are considered
balanced. If thealgebraic sum is
not equal to zero, the forces are
not balanced. The non-zero sum
is the net or unbalanced force.
This unbalanced or net force
would cause a change in a
body’s state of motion.

13. MASS AND WEIGHT
Quatity of matter which the
body contains
It is a scalar quantity
Unit of mass is Kg
Is the force on a
body due to gravity
It is a vector quantity
Unit of weight is N