# Forces

What does Newtons Third Law say?
when 2 ojects interact, the forces that they exert are equal and opposite
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Whats a vector quantity?
These have a magnitude and a direction
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3 Examples of vector quantities
displacement, force, acceleration
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What is a scalar quantity?
These only have a magnitude and no direction
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3 Examples of scalar quantities
temperature, speed, distance
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What are vector quantities represented by?
arrows
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What does the length of the arrow for vectors represent?
shows the magnitude
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1 Example of a contact force
friction
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What is a contact force?
When 2 objects have to be tocuhing for a force to act
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What is a non-contact force?
When objects dont need to be touching for a force to act
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1 example of a non-contact force
gravitational force
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What is meant by the phrase interaction pair?
a pair of forces that are equal and oppoiste and act on two interacting objects
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What are 2 effects of things being closely attracted to planets/ stars?
1. It gives everything a weight. 2. Makes all things on planets surface to fall to ground
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What is mass?
amount of stuff in an object
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What is weight?
force acting on an object due to gravity
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What is weight measured in?
Newtons (N)
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What is mass measured in?
Kilograms (Kg)
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What is meant by the term centre of mass?
a point at which you assume the whole mass is concentrated
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What is the equation for weight?
weight = mass x gravitational field strength
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What are the units for gravitational field strength?
N/Kg
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What does it mean by the term resultant force?
The overall force on a point or an object
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Equation for work done?
work done = force x distance
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What does equilibrium mean?
If all the forces acting on an object combine to give a resultant force of 0, then the object is equilibrium
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What is moment?
The turning effect of a force
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What is the equation for moment?
moment = force x distance
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What does distance actually mean in the equation for moment?
The perpendicular distance to from the pivot to he line of action of the force
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What do levers do?
increase the distance from pivot at which the force is applied
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What do gears do?
transmit rotational effects
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What happens when gear teeth interlock?
turning one gear, causes another one to turn but in the opposite direction
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Why will a force given to a larger gear cause a bigger moment?
because the distance to the pivot is bigger
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Do smaller or bigger gears turn faster?
small
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What is the definition of distance?
How far an object has moved
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What quantity is distance?
scalar
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What is the definition of displacement?
Measures the distance adn direction in a straight line from an objects starting point to end point
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Why is distance a scalar quantity?
Because it doesnt involve a direction
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What is meant by speed?
how fast you are going with no regard to a direction
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What is velocity?
the speed in a given direction
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What is the equation for distance travelled?
distance travelled = speed x time
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What is the equation for speed?
speed = distance / time
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What does acceleration mean?
change in velocity in a given time
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equation for acceleration?
acceleration = change in velocity / time
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what does deceleration mean?
negative acceleration
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What does uniform acceleration also mean?
constant acceleration
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what is the equation for uniform acceleration?
v(squared) - u (squared) = 2as
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V in SUVAT =?
Final velocity
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U in SUVAT =?
Initial velocity
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a in SUVAT =?
Acceleration
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s in SUVAT =?
Distance
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t in SUVAT =?
Time
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On distance-time graphs, what does the gradient equal?
speed
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On distance-time graphs, what do flat sections mean?
something is stationary
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What does stationary mean?
something isnt moving
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On distance-time graphs, what do straight, uphill lines mean?
travelling at a constant speed
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On distance-time graphs, what do curves mean?
either acceleration or deceleration
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On velocity-time graphs, what does the gradient equal?
acceleration
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On velocity-time graphs, what do flat sections mean?
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On velocity-time graphs, the stepper the graph...
the bigger accelration or deceleration
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On velocity-time graphs, downhill sections mean...
deceleration
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On velocity-time graphs, what do curves mean?
changing acceleration
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## Other cards in this set

### Card 2

#### Front

Whats a vector quantity?

#### Back

These have a magnitude and a direction

### Card 3

#### Front

3 Examples of vector quantities

### Card 4

#### Front

What is a scalar quantity?

### Card 5

#### Front

3 Examples of scalar quantities