Download Introduction_to_Forces

What is a Force?
Draw a picture or give a definition.
Write a mathematical equation to show
what makes a force stronger or weaker.
FORCES
When you ride a bike, your foot PUSHES against the
pedal. The push makes the wheels of the bike move.
When you drop something, it is PULLED to the ground
by gravity.
FORCES
A FORCE is a PUSH or PULL in a
particular DIRECTION.
Sometimes, a force is also a twist!
FORCES
FORCES AFFECT HOW OBJECTS MOVE.
Forces can affect motion in the following ways:
They can make objects:
BIG
SCIENCE
IDEA
i) START MOVING
ii) MOVE FASTER
iii) MOVE SLOWER
iv) STOP MOVING
v) CHANGE DIRECTION
vi) CHANGE SHAPE
FORCES
Since forces cause changes in SPEED
or DIRECTION of an object, we can say
that….
Forces cause
ACCELERATION.
There are lots of different types of
forces
This can be any driving force, it may be a push or
pull, but it could be an engine which forces an
object forward.
This is the force required to raise an object
through a fluid
This is a force which acts in the air, it can slow
objects down when they are moving against it. Or
if harnessed could be used to move an object
along.
This force acts on objects when they are in
contact with a surface, such as the ground. It can
be reduced by ensuring both surfaces are
smooth.
This force affects every object on Earth. It is a
force which pulls everything to the centre of the
earth.
This is an upward force which acts against
gravity. The reason that you do not fall through
the earth is due to this force.
Other forces can’t be seen but form fields. Examples of this
would be magnetic fields and electromagnetic fields.
We use arrows to represent forces
on objects.
Motive Force (Thrust)
1000 Newtons
We always
measure forces
in Newtons
07/05/2017
Balanced and unbalanced forces
Consider a camel standing on a road.
What forces are acting on it?
Reaction
These two forces would be equal –
we say that they are BALANCED.
The camel doesn’t move anywhere.
Weight
07/05/2017
Balanced and unbalanced forces
Reaction
What would happen if we took the
road away?
The camel’s weight is no longer
balanced by anything, so the camel
falls downwards…
Weight
Group Activity: What forces are acting on
this car which is driving along?
(label the diagram with arrows showing the
direction and type of force)
For bonus points: Can you make the size of the arrows proportional to the
force(s) acting on the car?
Group Activity: What forces are acting on
this car which is driving along?
This acts against the car, as
it moves forward and is
acting against the
propulsion.
This force is always
present. It goes
towards the centre of
the earth, so will
always be pointing from
the top of the object
Thrust
This is the most powerful
force, this should be your
largest arrow, it should be
pointing in the direction the
car is going …
Reaction
This force is only present
where the car is in contact
with the floor, it acts against
the propulsion.
Balanced and unbalanced forces
07/05/2017
Resultant
Forces
If the forces on an object
are unbalanced we say
that a RESULTANT
FORCE acts on the
object.
Resultant force.
A resultant force is a single force that
can replace all the forces acting on an
object
Resultant forces cause the object to accelerate
or in some cases change shape. If the forces
are balanced we can say the resultant force is
ZERO
and
the
object
will
not
change
its
velocity
ALSO: forces at right angles to each other
(or
shape).
have no effect on each other.
=
What is the Resultant Force?
5N
The resultant force is 1N to the right
4N
What is the Resultant Force?
3N
The resultant force is 3N to the left
6N
What is the Resultant Force?
5N
There is no resultant force
5N
What is the Resultant Force?
7N
The resultant force is 11N to the right
4N
What is the Resultant Force?
8N
The resultant force is 5N to the left
3N
What are the Resultant Forces?
1N
2N
9N
1N
The resultant force is 7N to the right
What are the Resultant Forces?
6N
8N
7N
5N
The resultant force is 1N to the left and 1N up