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### 66 Cards in this Set

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 What are some examples of fossil fuels? natural gas oil coal *The world is slowly running out of fossil fuels. How are fossil fuels formed? Fossil fuels are formed from the remains of once-living organisms. They are nonrenewable resources. What is the world's most widely used fossil fuel? Petroleum What are some other energy technologies? Wind, solar and hydroeclectric energy. What force keeps the planets in orbit? Gravity The amount of matter in an object. Mass A measure of the pull of gravity on an object. Weight What 3 forces affect Earth and the objects on Earth every day? Friction Magnetism Gravity "Forces 1-2-3....F-M-G" F M G A push or a pull that can make an object speed up, slow down or change direction. Force A change in movement (speeding up, slowing down or changing direction) Acceleration What force attracts all objects toward eachother? Gravity When an object's motion changes, you know that the forces acting on it are ________________________. unbalanced A force that acts on an object does ___________ only when the object moves. work A _______________ makes work easier by trading force for distance. machine ___________________ act on an object without causing a change in the object's motion. They cancel eachother out. balanced forces A force of repulsion or attraction between objects with two poles magnetism When you rub or slide one object over another, the force of ______________ acts in the opposite direction. friction Why do a magnet's poles point north and south? Because Earth is a huge magnet and its magnetic field causes the needle of a compass to point north and south. Like poles of a magnet _______________ eachother. repel Opposite poles of a magnet brought together ___________________ eachother. attract The greater an object's ___________, the greater its gravity. mass An astronaut's weight on the moon is (1/3, 1/6, 1/8) his or her weight on Earth? 1/6 The greater the distance between two objects, the (more or less?) force of gravitation acts on them? less Satrun has more mass than Eath. On Saturn, the force of gravity would be much (greater/less) and you would be much (heavier/lighter). On Saturn, the gravity is greater and you would be heavier. _______________ forces are equal in size and opposite in direction. Balanced If balanced forces act on a still object, will it appear to move? No ___________________ always act in pairs. Forces What happens to an object's motion when unbalanced forces act on it? It will ACCELERATE (move, speed up, slow down, stop or change direction). Note: ANY change in motion--even slowing down or a stop-- is called an acceleration. What is the net force when a force of 100 newtons pushes against a force of friction of 80 newtons? Net force = 100 - 80 = 20 newtons What is the net force when a force of 100 newtons pushes in the same direction as a force of 100 newtons? Net force = 100 + 100 = 200 newtons What is the net force when a force of 100 newtons pushes against a force of 100 newtons? Net force = 100 - 100 = 0 newtons If balanced forces act on an object that is moving, will it result in a change in the object's speed? No If a book weighs 35 newtons and you apply a force of 50 newtons to lift it, what is the net force acting on the book? Net force = 50 up - 35 down = 15 newtons going up. Which law of motion: An object at rest will remain at rest, and an object in motion will continue moving in a straight line at a constant speed until an outside force acts on it. The First Law of Motion Which law of motion is also known as the Law of Inertia? The First Law of Motion Someone pulls a tablecloth out from under a table setting and the items remain in place on the table. How is this possible? The INERTIA of the objects on the table keeps them in place. In space, where there's microgravity, is it easier or harder to loosen or tighten a screw? Why? It's harder, because there's much less gravity to hold you in place. You'd need something to brace against. When did Newton formulate the Laws of Motion? In the 1600's. When a leaf falls from a tree what is the force acting on the leaf? Gravity You can exert a force on an object, but only if it moves did you do __________ work "An object's acceleration depends on the SIZE and DIRECTION of the force acting on it and on the MASS of the object." Which Law of Motion is this? The Second Law of Motion A rolling soccer ball will speed up if it's kicked from behind. Which law of motion does this represent? The Second Law of Motion A ball on a flat, level surface stays where it is because it is left alone. Which law of motion does this represent? The First Law of Motion (The ball is remaining at rest) A spacecraft continues moving at the same speed and in the same direction, practically forever. Which law? The First Law of Motion F = M x A CHECK THIS FORMULA FOR ACCURACY. Which law is this? What does it mean? Force = Mass x Acceleration The Second Law of Motion What happens to an object's acceleration as the size of the force acting on the object increases? The object's acceleration increases. "For every action, there is an equal and opposite reaction." Which law? The Third Law of Motion A rocket engine pushes burning gases out the back of the rocket. The gases provide the force that move the rocket forward. Which law? The Third Law of Motion The action of the burning gases pushing down produce an equal and opposite reaction of the rocket moving up. If an astronaut throws an object into space, what happens to the object? It keeps going practically forever, because there's little friction in space. How is the chemical energy stored in fossil fuels released? Through burning (Burning fuels produce thermal energy.) What measurement is used to measure energy? Joules List 4 fossil fuels. Describe what they do. Coal Oil Natural gas They release lart amounts of thermal energy when burned, so they're useful for transportation, cooking food, heating Which force resists motion? friction Which law is a math formula The Second Law of Motion What are the conditions responsible for the formation of coal, oil and natural gas? Fossil fuels come from the remains of living organisms that were deep inside the Earth for millions of years. What other technologies are an alternative to fossil fuels? Why should we use them? Wind energy Geothermal energy Because they are inexhaustible Why is it difficult to run on ice? There's less friction What is the change in position over time? Motion The resistance of an object to a change in speed or direction is which law? The First Law of Motion What is the unit of force? Newton Why do the other planets revolve around the sun? The sun's mass is larger than the other planets. When gravity is the force actin on an object, do all objects fall at the same or different rate? All objects fall at the same rate. How do we describe motion? To describe motion, we measure: The change in Speed, Direction and Acceleration in speed over time (ex. 60 miles per hour). Hockey puck doesn't move unless something hits it. Would slide in a straight line if something stopped it. This is an example of: The First Law of Motion 1st Law: Inertia 2nd Law: Motion 3rd Law: For every action, there's an equal and opposite reaction 1st: Inertia 2nd: Motion 3rd: Action/reaction Examples of friction: Road slowing wheels Air slowing plane Water slowing boat