FORCES IN ACTION MACHINES MOVE THE WORLD UNIT 2 Marta Vidal Vidal L3L3 L4 L5 L6L4L5L6

ISAAC NEWTON ISAAC NEWTON ( ) FIRST LAW OF MOTION. INERTIAINERTIA 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.

Unbalanced Unbalanced force Start motion Stop motion Change direction Change shape

BalancedBalanced force No change No visible effect

WHICH 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.

HANDS 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

HANDS 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 T1+T2+T3 3 Aluminium foil cm Wax paper cm Recycled paper cm Sand paper cm

HANDS 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.

HANDS ON! Friction PROBLEM: How do different surfaces affect the movement of the objects?different surfaces STEPS: 3. Drop the toy car and measure the distance. 4. Do 3 different trials for each surface and calculate the total distance. SURFACE PREDICTION cm TRIAL 1 cm TRIAL 2 cm TRIAL 3 cm DISTANCE T1+T2+T3 3 Aluminium foil cm Wax paper cm Recycled paper cm Sand paper cm Total distance = trial 1 + trial 2 + trial 3 3

WEIGHT 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 ENGLISH DECIMALS IS IN. (DOT) SPANISH DECIMALS IS IN, (COMMA)

Our MASS is the same everywhere but if we travel over the universe we have a different WEIGHT MASS = 60 Kg WEIGHT = 60 Kg MASS = 60 Kg WEIGHT = 60 x 0.16 WEIGHT = 9.6 Kg What will happen to our weight if we travel around space?

Calculate your weight in the Solar System Planets, Star and satellite GRAVITY MULTIPLIED BY your MASS IS EQUAL TO your WEIGHT Sun27,90 Mercury0,37 Venus0,88 Earth1,00 Mars0,38 Jupiter2,64 Saturn1,15 Uranus0,16 Neptune1,22 Moon0,16 Look at the gravity of the planets, the sun and the Moon and calculate your weight in respect to those.

Is it your weight different or is it equal? My weight never changes. changes. Is it your mass different or is it equal? My massnever changes. changes. Look at your results and underline the correct part of the sentence. On EarthOn the moon Weight = mass x gravity in newtons WEIGHT = ………. x 9,8WEIGHT = ………. x 1,5 WEIGHT = ….....newtons Calculate your weight in newtons

WHAT IS FORCE? It can be a PUSH or a PULL. PUSH or a PULL PUSH PULL FORCE OBJECT

Is it a push or a pull?

ISAAC NEWTON ISAAC NEWTON ( ) SECOND LAW OF MOTION. 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 THE UNIT FOR THE FORCE IS IN NEWTONS F F

HANDS ON! Newtons ObjectsPREDICTIONMASS FORCE NEWTONS Result PROBLEM: How do you use a dynamometer? What is the relationship between mass and force? MATERIALS: - Pencil - Tape measure - Weighing scale - Dynamometer - 3 objects. 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).

HANDS ON! Newtons ObjectsPREDICTIONMASS FORCE NEWTONS Result PROBLEM: How do you use a dynamometer? What is the relationship between mass and force? MATERIALS: - Pencil - Tape measure - Weighing scale - Dynamometer - 3 objects. STEPS: 2. Measure the objects with a weighing scale and record it in your data table.

HANDS ON! Newtons ObjectsPREDICTIONMASS FORCE NEWTONS Result PROBLEM: How do you use a dynamometer/spring scale? What is the relationship between mass and force? MATERIALS: - Pencil - Tape measure - Weighing scale - Dynamometer - 3 objects. 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.

HANDS ON! Newtons PROBLEM: How do you use a dynamometer? What is the relationship between mass and force? MATERIALS: - Pencil - Tape measure - Weighing scale - Dynamometer - 3 objects. STEPS: 5. Write your conclusion about the experiment. 6. Share and check the results with the whole class. 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.

ISAAC NEWTON ISAAC NEWTON ( ) 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.

GRAVITY NON-CONTACT FORCES CONTACT FORCES PULL PUSH FORCE FRICTION 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. It is the force resisting the relative motion of solid surfaces, fluid layers, and/or material elements sliding against each other. It is any influence that causes a free body to undergo a change in speed, a change in direction, or a change in shape. It is a force that can move something away from somebody/something. It is a force that can move something towards somebody/something. It is a force applied to an object by another body that is not in direct contact with it. It is a force that acts at the point of contact between two objects.