C4 (Forces in Action) Flashcards

1
Q

What does the mass of an object depend on

A

Amount of matter it cotains

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2
Q

A net force acting on the object will make the object will make it…

A

Accelerate if the direction of the net force

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3
Q

Equation for resultant force

A

F=ma

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4
Q

Equation for weight

A

W=mg

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5
Q

Where would the resultant force on the object (it’s total weight) will act through a point often called…

A

The objects centre of gravity

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6
Q

Why do we use the centre of mass

A

Much easier to analyse and solve physics problems

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7
Q

How do you find the centre of gravity

A

Using a plumb line

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8
Q

Weight

A

The gravitational force acting on an object through its centre of mass

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9
Q

Friction

A

The force that arises when two surfaces rub against each other

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10
Q

Drag

A

The resistive force on an object travelling through a liquid, the same as friction

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11
Q

Tension

A

The force within a stretched cable or rope

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12
Q

Normal contact force

A

A force arising when one object rests against another object

Normal means at a right angle too

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13
Q

Assuming there’s no friction what’s the only force acting on an object

A

It’s weight

Which can be resolved into two components, parallel and perpendicular to the slope.

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14
Q

An object moving through an object experiences what

A

Drag

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15
Q

Drags magnitude depends on several factors…

A

Speed of object
Shape of object
Roughness and texture
Density of the fluid through which it travels
Most important factors are it’s speed and cross sectional area

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16
Q

What is drag directly proportional to?

A

Speed^2

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17
Q

What does having a vehicle that’s more smooth and streamline permit

A

Increase top speed and reduces the amount of fuel used on a journey

18
Q

Terminal velocity

A

When the drag force on the object is equal and opposite to it’s weight . At terminal velocity the object has zero acceleration and it’s speed is constant.

19
Q

Moment of a force

A

The turing effect of a force about some axis or point

20
Q

Moment equation

A

Moment= force x perpendicular distance of the line of action form the axis/point of rotation

21
Q

The principal of moments

A

When body is in equilibrium the net force and it’s net moment is 0.
For a body in rotational equilibrium, the sum of the anticlockwise moments about any point is equal to the sum of the clockwise moments about the same point.

22
Q

Torque of a couple

A

One of the forces x perpendicular separation between the forces
=Fd

23
Q

Torque

A

A moment of a couple

24
Q

Couple

A

Two forces that must be parallel and along different lines.

25
How can forces in equilibrium be drawn
Triangle of forces ( an enclosed triangle as the forces are in equilibrium)
26
Density
Mass per unit of volume | Density=m/v
27
Pressure equation
Pressure = Force/ Area
28
What are fluids
Substances that can flow
29
How to calculate pressure exerted by a vertical column of any liquid
p= height x density x gravitational potential
30
The pressure in a fluid at any particular depth has an unusual feature are
It is the same in all directions
31
Upthrust is based on what
Pressure difference
32
Archimedes principle
The upthrust exerted on a body immersed in a fluid, wether fully or partially submerged, is equal to the weight of the fluid that the body displaces
33
When will an object sink
If the upthrust is less than the weight of the object
34
Density
Is the mass per unit volume
35
Pressure
Is the force per unit area
36
2 equations for pressure
P=F/A | P=hpg
37
Upthrust
An upward force that fluids excerpt on objects that are partially or fully submerged in the fluid. Occurs because of the pressure difference between the top and bottom of the object.
38
Upthrust is equal to...
The weight of the fluid displaced
39
Archimedes's principle
Says that when a body is completely or partially immersed it experiences an upthrust equal to the weight of the fluid it has displaced
40
Power equation
Power= Force x Velocity
41
Most car safety features are designed to slow you down gradually Give some examples
Seat belts Air bags Crumple zones