Title: FORCES IN ACTION
1FORCES IN ACTION
UNIT 2
MACHINES MOVE THE WORLD
Marta Vidal Vidal
L3 L4 L5 L6
2ISAAC NEWTON (1642-1727)
- FIRST LAW OF MOTION. INERTIA
- An object at rest stays at rest,
- an object in motion stays in motion.
Why does an object stop its motion?
Why do objects change its direction?
Because it is the result of an UNBALANCED FORCE
applied upon an object.
3Unbalanced force
- Start motion
- Stop motion
- Change direction
- Change shape
4Balanced force
- No change
- No visible effect
5WHICH FORCES INFLUENCE MOTION?
- Contact forces
- Friction
- Push/Pull
- Weight
- Non-contact forces
- Gravity
- Magnetism superconducting
FORCE is any influence that causes a free body
to undergo a change in speed, a change in
direction, or a change in shape.
6HANDS ON! Friction
- PROBLEM
- How do different surfaces affect the movement of
the objects? -
- MATERIALS
- Pencil, toy car, metric tape, 4 clothespegs,
tape, scissors, aluminium foil, wax paper,
recycled paper, sand paper, a calculator and
plastic cable covers. -
- STEPS
- 1. Predict the distance of the toy car on each
surface. - 2. Create a ramp using 4 clothespegs and plastic
cable covers. - 3. Drop the toy car and measure the distance.
- 4. Do 3 different trials for each surface and
calculate total distance. -
-
-
- Play with friction
7HANDS ON! Friction
- PROBLEM
- How do different surfaces affect the movement of
the objects? - STEPS
- 1. Predict the distance of the toy car on each
surface. -
SURFACE PREDICTION cm TRIAL 1 cm TRIAL 2 cm TRIAL 3 cm DISTANCE T1T2T3 3
Aluminium foil cm
Wax paper cm
Recycled paper cm
Sand paper cm
8HANDS ON! Friction
- PROBLEM
- How do different surfaces affect the movement of
the objects? -
- STEPS
- 2. Create a ramp using 4 clothespegs and plastic
cable covers. -
-
-
9HANDS ON! Friction
- PROBLEM
- How do different surfaces affect the movement of
the objects? -
- STEPS
- 3. Drop the toy car and measure the distance.
- 4. Do 3 different trials for each surface and
calculate the total distance. -
-
Total distance trial 1 trial 2 trial 3
3
SURFACE PREDICTION cm TRIAL 1 cm TRIAL 2 cm TRIAL 3 cm DISTANCE T1T2T3 3
Aluminium foil cm
Wax paper cm
Recycled paper cm
Sand paper cm
10WEIGHT
ENGLISH DECIMALS IS IN . (DOT) SPANISH DECIMALS
IS IN , (COMMA)
- MASS is a measurement of how much matter is in an
object. - WEIGHT is a measurement of how hard gravity is
pulling on that object. - On Earth 1 kg of mass 9.8 newtons
- Gravity on Earth is 1G 9.8 newtons
- WEIGHT MASS x GRAVITY
- WEIGHT 1kg x 1 1
- WEIGHT 1 Kg or
is 9.8 newtons - On Earth our mass is equal to our weight.
- MASS 1kg WEIGHT 1kg
11- Our MASS is the same everywhere but if we travel
over the universe we have a different WEIGHT
What will happen to our weight if we travel
around space?
MASS 60 Kg WEIGHT 60 Kg
MASS 60 Kg WEIGHT 60 x 0.16 WEIGHT 9.6 Kg
12Calculate your weight in the Solar System
Look at the gravity of the planets, the sun and
the Moon and calculate your weight in respect to
those.
Planets, Star and satellite GRAVITY MULTIPLIED BY your MASS IS EQUAL TO your WEIGHT
Sun 27,90 MULTIPLIED BY IS EQUAL TO
Mercury 0,37 MULTIPLIED BY IS EQUAL TO
Venus 0,88 MULTIPLIED BY IS EQUAL TO
Earth 1,00 MULTIPLIED BY IS EQUAL TO
Mars 0,38 MULTIPLIED BY IS EQUAL TO
Jupiter 2,64 MULTIPLIED BY IS EQUAL TO
Saturn 1,15 MULTIPLIED BY IS EQUAL TO
Uranus 0,16 MULTIPLIED BY IS EQUAL TO
Neptune 1,22 MULTIPLIED BY IS EQUAL TO
Moon 0,16 MULTIPLIED BY IS EQUAL TO
13Look at your results and underline the correct
part of the sentence.
Is it your weight different or is it equal? Is it your weight different or is it equal? Is it your weight different or is it equal? Is it your weight different or is it equal? Is it your weight different or is it equal?
My weight My weight never changes. changes. never changes. changes.
Is it your mass different or is it equal? Is it your mass different or is it equal? Is it your mass different or is it equal? Is it your mass different or is it equal? Is it your mass different or is it equal?
My mass never changes. changes. never changes. changes.
Calculate your weight in newtons
On Earth On the moon
Weight mass x gravity in newtons Weight mass x gravity in newtons
WEIGHT . x 9,8 WEIGHT . x 1,5
WEIGHT .....newtons WEIGHT .....newtons
14WHAT IS FORCE?
- It can be a PUSH or a PULL.
15Is it a push or a pull?
16ISAAC NEWTON (1642-1727)
THE UNIT FOR THE FORCE IS IN NEWTONS
The strength of a force is equal to the amount of
the mass involved multiplied by any acceleration
applied to it. F m x a If the mass is bigger
the effect of the FORCE is smaller If the
mass is smaller the effect of the FORCE is
bigger
17HANDS ON! Newtons
MATERIALS - Pencil - Tape measure - Weighing
scale - Dynamometer - 3 objects.
PROBLEM How do you use a dynamometer? What is
the relationship between mass and force?
STEPS 1. Predict the power of the force needed
to move the objects. Write a number from 1 to 3
(from bigger force to a smaller force).
Objects PREDICTION MASS FORCE NEWTONS Result
18HANDS ON! Newtons
MATERIALS - Pencil - Tape measure - Weighing
scale - Dynamometer - 3 objects.
PROBLEM How do you use a dynamometer? What is
the relationship between mass and force?
STEPS 2. Measure the objects with a weighing
scale and record it in your data table.
Objects PREDICTION MASS FORCE NEWTONS Result
19HANDS ON! Newtons
MATERIALS - Pencil - Tape measure - Weighing
scale - Dynamometer - 3 objects.
PROBLEM How do you use a dynamometer/spring
scale? What is the relationship between mass and
force?
STEPS 3. Put a tape measure on the floor and
measure 100 cm in straight line. 4. Attach the
object to the dynamometer and pull it along a
distance of 100 cm and record the result in your
data table.
Objects PREDICTION MASS FORCE NEWTONS Result
20HANDS ON! Newtons
MATERIALS - Pencil - Tape measure - Weighing
scale - Dynamometer - 3 objects.
PROBLEM How do you use a dynamometer? What is
the relationship between mass and force?
STEPS 5. Write your conclusion about the
experiment. 6. Share and check the results with
the whole class.
Write your CONCLUSIONS Write your CONCLUSIONS Write your CONCLUSIONS Write your CONCLUSIONS
If the mass of an object is bigger smaller the force needed to move it is bigger smaller.
If the mass of an object is bigger the force
needed to move it is bigger.
If the mass of an object is smaller the force
needed to move it is smaller.
21ISAAC NEWTON (1642-1727)
THIRD LAW OF MOTION ACTION AND
REACTION All forces occur in pairs. For
every action that takes place there is an equal
and opposite reaction.
22FORCE
It is any influence that causes a free body to
undergo a change in speed, a change in direction,
or a change in shape.
CONTACT FORCES
It is a force that acts at the point of contact
between two objects.
It is the force resisting the relative motion of
solid surfaces, fluid layers, and/or material
elements sliding against each other.
FRICTION
PULL
It is a force that can move something towards
somebody/something.
PUSH
It is a force that can move something away from
somebody/something.
NON-CONTACT FORCES
It is a force applied to an object by another
body that is not in direct contact with it.
MAGNETISM
Force of attraction or repulsion acting between
ferromagnetic materials like iron.
It is a force that pulls all objects towards the
center of the Earth.
GRAVITY