# Physics-Mechanics

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• Created by: JamieH98
• Created on: 06-04-13 21:08
How do you calculate average speed?
Average speed=total distance travelled/ journey time
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What is instantaneous speed?
Instantaneous speed is when the distance and the time are short
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How do you measure acceleration given two speeds and a time?
a=v-u/t
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What is acceleration and what is it measured in?
Acceleration is the rate of change of speed and is measured in m/s²
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What is dynamics?
Dynamics is the study of forces
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What is weight?
Weight is the force produced by one object with mass pulling another object with mass.
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How are weight and mass connected?
Weight is directly proportional to mass
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How do you calculate weight?
W=mg
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What is friction?
• Frcition is the force which opposes motion and occurs when two surfaces move over each other
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What is force measured in?
Force is measured in N
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Name a force other than friction that opposes motion?
Another force which opposes motion is drag or air resistance
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How do you reduce drag?
• To reduce drag we can- reduce the area presented to the flow fluid; reduce turbulence by streamlining and reduce surface roughness
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Give an example of reducing drag?
An example of reducing drag would be a cyclist
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How do you reduce friction?
To reduce friction we can- smooth the surface and lubricate it.
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Give an example of reducing friction?
An example of reducing friction is skiing
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What is high friction important for?
However, high friction is important for: tyres; shoes and brakes
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How do you measure speed when given acceleration instead of distance and a time?
v=at
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What is Newton's first law of motion?
• Newton's first law states that if the forces acting upon an object are balanced the object will either be at rest or moving at a constant speed in a straight line.
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What is Newton's second law of motion?
Newton's second law is F=ma
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What is the resultant force?
• The resultant force is an imaginary force which would have the same effect as all the forces acting on an object
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What is Newton's third law?
• Newton's third law "for every action there is an equal and opposite reaction"
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What is a Newton's pair and give an example?
• A newton's pair is a pair of objects which have an equal and opposite reaction for example the weight of a parachutist going down and the gravitational force on earth pushing up.
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Name all the types of energy?
• Types of energy are: kinetic; gravitational potential; stain potential; chemical; heat; light; sound; nuclear; electrical and electromagnetic
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What is the first law of thermodynamics?
• The first law of thermodynamics says that energy cannot be created or destroyed, only changed from one form to another
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What is work done?
• When energy is converted from one form to another by a machine the quantity of energy transformed is called work done Ew
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What is energy measured in?
Energy is measured in J
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How do you calculate work done?
Ew=Fd
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How do you calculate potential energy?
Ep=mgh
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What is gravitational field strength measured in?
Gravitational field strength is measured in N/Kg
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How do you calculate kinetic energy?
Ek=1/2mv²
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How do you calculate power?
P=E/t
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What is power measured in?
Power is measured in J/s or W
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What is power?
Power is the measure of how quickly a machine can convert energy from one form to another
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What is 1W equal to?
1W=1J/s
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How do you calculate energy?
E=pt
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How do you calculate efficiency?
Efficiency=useful energy output/total energy input×100
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## Other cards in this set

### Card 2

#### Front

What is instantaneous speed?

#### Back

Instantaneous speed is when the distance and the time are short

### Card 3

#### Front

How do you measure acceleration given two speeds and a time?

#### Back ### Card 4

#### Front

What is acceleration and what is it measured in?

#### Back ### Card 5

#### Front

What is dynamics?

#### Back 