# Mechanics

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What is distance?
How far you have covered (meters)
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What is displacement?
How far you're from the beginning point
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What is the equation for speed?
Total displacement / time take
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What is acceleration?
Rate of change of velocity (speed)
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What is the equation for acceleration?
Change in velocity / time taken
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What does the area under the velocity time graph give?
Total displacement in that time
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What are constant acceleration equations?
Standard set of letters used for motion of an object moving in a straight lines with constant acceleration
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What are the constant acceleration equations?
v=u+at, s=1/2(u+v)t, s=ut + 1/2at^2, s=vt-1/2at^2, v^2=u^2 + 2as
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What is the method for the constant acceleration formulas?
i. List what you know ii. Find the equation required iii. Solve equation to find info
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How do you find the magnitude of the displacement covered?
Pythagoras
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How is a bearing measured?
From the point north line clockwise
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What is the magnitude of displacement?
Distance
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How do you find displacement from vectors?
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What is the displacement of vectors called?
The position vector
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What is the magnitude of velocity?
Speed
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What is the equation of the average velocity?
Displacement from starting point / time taken or Change in position vector / time taken
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How do you calculate the resultant velocity?
end on end - then Pythagoras, cosine or resolving
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What is acceleration when there is constant velocity?
0
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What is the method for finding the resultant force?
i. Scale drawing ii. Calculate with trig
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What are coplanar forces in equilibrium?
Forces acting on the same plane eq flat surface
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What is weight?
An object being pulled vertically down
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What is tension?
A pulling force eq rope pulling
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What is thrust?
A pushing force
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What are assumptions with weight, thrust and tension?
All objects thought of as a point/particle, therefore all forces act on the same point (no thrust ect)
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What happens as pulling and friction force increases?
The object remains in equilibrium
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What happens when the limit to which the surface can resist is exceeded?
The object moves, and accelerates
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What is the object when it is just about to move?
Limiting equilibrium
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What is the maximum friction force proportional to?
The normal reaction
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What does friction force equal?
µR
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What is µ?
Coefficient of friction
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What is the coefficient of friction?
A required roughness of the interface between 2 surfaces
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What happes as µ gets bigger?
The roughness of the surface increases
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What will mgsinQ cause when a box is on a slope?
acceleration down the slope
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What does it mean if T = mgsinQ?
no acceleration
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What does it mean if T>mgsinQ?
Acceleration up the slope
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What does it mean if T
Acceleration down the slope
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What would happen in the absence of air resistance?
All objects fall to earth with the same constant acceleration
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What is the N2L formula?
F=mxa
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What are the assumptions of newtons 2nd law of motion?
The object is thought of as a particle (all forces acting on one point), Any cables treated as 'light' and cables in extensible
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What is Newtons third law?
'Action + reaction are equal and opposite'
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What are assumptions with pegs and pulleys?
Light string and smooth peg
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What do you assume if there is a smooth surface?
No friction
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What is the equation for momentum?
Mass x velocity
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What is the momentum before and after?
Equal
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What does coalesce mean?
Join together
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What is the equation of momentum if there is a force?
Force x time
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What happens if an object moving in a straight line at a constant velocity has a force acting on it?
The momentum will change
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What is the acceleration if an object is thrown upwards?
-9.8ms-2
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What is the acceleration if an object is dropped downwards?
9.8ms-2
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What is the only force on free falling objects?
Weight
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What are assumptions of projectiles?
Object is modelled as a particle and no air resistance/spin
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Where is the minimum speed of a projectile?
At the top
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How should you prepare for projectiles?
Set up equations: v=u+at & s=ut+1/2at^2
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How should you work out time of flight?
Bottom of 'S' = 0
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What is time of flight?
Distance vertically
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How should you work out the range of a projectile?
Top line of 's'
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How can you find out where it starts?
Top = 0
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How do you find out the maximum point?
Bottom of V = 0
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## Other cards in this set

### Card 2

#### Front

What is displacement?

#### Back

How far you're from the beginning point

### Card 3

#### Front

What is the equation for speed?

### Card 4

#### Front

What is acceleration?

### Card 5

#### Front

What is the equation for acceleration?