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18 Cards in this Set
- Front
- Back
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[FORCE] What kind of quantity is force? and what must you take account of? |
vector quantity magnitude and direction |
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difference between contact and non-contact forces? |
contact forces act between two objects only when they touch (eg. golf ball hit by club) while non-contact forces act even when they don't touch (eg. magnets) |
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What is Newton's first law? |
The Law of Inertia an object stays at the same speed (rest or motion) unless acted upon by an unbalanced force eg. friction |
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What is Newton's second law? |
When an unbalanced force acts on a body, it produces acceleration in the direction of the unbalanced force. F = ma Force = mass*acceleration |
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What is Newton's third law? |
For every action there is an equal and opposite reaction force |
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What's the formula for weight? |
Fw = mg Fw = weight in Newtons (N) g = gravity (9.8m/s-2) ex. 5x9.8= 49N |
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[ENERGY] What is work and what is it measured in? |
Work is when a force moves and object through a displacement measured in joules (J) (energy is converted from one form to another) |
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What is power and what is it measured in? |
Power is the rate of doing work measured in watts (W) (the rate at which energy is expended, transferred or transformed) |
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What is kinetic energy? |
Energy possessed by a moving object. (KE = 1/2m*v^2) |
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What is gravitational potential energy? |
When an object is lifted from the ground, work is done against gravity. This work is stored in the object as gravitational PE. |
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What does conservation of PE and KE mean? |
When the only energy changes that take place in a body are from PE to KE or vice-versa, the total of PE and KE remains constant. |
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What does it mean when something is efficient? |
When energy produced by something doesn't go to waste energy (eg. a car and wasted heat energy) |
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[ELECTROMAGNETICS] What do electromagnetic fields look like? |
Electromagnetic fields are very circular and surround a flow of charge. The right hand screw rule can be used to determine the direction of the field. |
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What is the motor effect? |
If a wire carrying current is placed perpendicular to a magnetic field it will experience force. |
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How do you find the direction of force? |
line up the current with your thumb and the magnetic field with your fingers, the force comes out of your palm. |
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When does induction occur and what does it create? |
When a magnet and a coil of wire move relative to each other, creating current. |
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How do AC generators work? |
Alternating current is generated by rotating the coil in a magnetic field. |
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how do transformers work? |
Alternating current is fed into one side of the transformer, producing an alternating magnetic field which is channeled to the other side. |
