Term
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Definition
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Term
| What effect does a force have? |
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Definition
It makes an object change speed or direction - in otherwords accelerate!
OR it could make an object rotate OR be deformed. |
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| What are forces measure in? |
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Definition
| newton (N) - must be a capital letter! |
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| Is a force a scalar or vector quantity? |
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Definition
| It is a vector - that is because the direction the force acts in makes a big difference. With scalars there is no directional element involved. |
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| How is a force represented on a diagram? |
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Definition
| By an arrow. The length of the arrow represents the SIZE of the force (sometimes called the magnitude of the force). The direction of the force is given by the orientation of the line and the arrow head. You should put a scale on your diagram. For example: 1cm represents 10N |
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| What is the term for a force that is pushing in the same direction as an object is already travelling in? |
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Definition
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Term
| What is the term for a force that is pushing in the opposite direction as that an object is already travelling in? |
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Definition
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Term
| If a driving force is applied to an object what does it make that object do? |
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Definition
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Term
| If a counter force is applied to an object what does it make that object do? |
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Definition
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Term
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Definition
| The single force that could replace a group of more than one forces acting on an object.
For example: if you have 10N pushing up on an object and 6N pushing down that is the same as having one force of 4N pushing up - so 4N up is the net force acting on the object. |
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Term
| If there is no net force acting on an object what will it do? |
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Definition
| It will not accelerate - it will keep on going at the same speed (which might be 0m/s!!) and in the same direction as it was doing before the system of forces that resulted in 'no net force' acted on it. |
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Term
| Sketch a diagram to show a 1N force to the left and a 3N force to the right. Then sketch a diagram to show the net force acting. |
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Definition
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Term
| Sketch a diagram to show a 2N force to the left and a 2N force to the right. Then sketch a diagram to show the net force acting. |
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Definition
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Term
| What is the equation that relates the size of the net force acting on an object to the acceleration is produces? |
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Definition
| F = ma
where: F = force in newtons (N)
m = mass in kilograms (kg) a = acceleration in metres per second squared (m/s2) |
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Term
| What is the acceleration due to gravity? |
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Definition
| The acceleration produced on all masses when they are near the Earth's surface is called the acceleration due to gravity. This is the same whatever the mass of the object! It is about 10m/s2. |
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Term
| When you fall from an aeroplane what force makes you accelerate downwards? |
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Definition
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Term
| When you parachute from an aeroplane what counter force acts on you? |
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Definition
| Drag or air resistance - the faster you go the bigger the air resistance force will be. |
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Term
| When you are in contact with a surface as you move what counter-force acts on you? |
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Definition
| Friction - the faster you go the bigger the frictional force will be and the bigger the area of you in contact with the surface the bigger the frictional force will be. |
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Term
| When you open a parachute what force increases? |
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Definition
| Air resistance increases - so you slow down. |
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Term
| What is Newton's first Law? |
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Definition
Newton's First Law, says that if the forces on an object are in balance, the object's speed and direction of motion won't change.
- Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. |
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Term
| What is Newton's Second Law? |
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Definition
| At a simple level it is that F=ma where: F = force in newtons (N)
m = mass in kilograms (kg) a = acceleration in metres per second squared (m/s2) A better definintion of it is that the rate of change in momentum of a body is the same as the force applied to it - but you won't come across momentum until GCSE. |
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Term
| What is Newton's Third Law? |
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Definition
| Newton's Third Law, says that every action has an equal and opposite reaction. This means that when you push or pull something, it pushes or pulls back at you. Forces are two-way affairs, they're about the way that objects affect each other. Newton's third law is one of the fundamental symmetry principles of the universe. Since we have no examples of it being violated in nature, it is a useful tool for analyzing situations with are somewhat counter-intuitive. For example, when a small truck collides head-on with a large truck, your intuition might tell you that the force on the small truck is larger. Not so! They both exert equal forces on each other.... but as the mass of the big truck is greater the change in its speed (what gives you a jolt if travelling in it!) is smaller so you feel less effect and THINK the force is smaller![image] |
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Term
| Which of Newton's Laws gets called the 'Law of Intertia'? |
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Definition
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