Forces Flashcards

1
Q

Principle of moments

A

when a lever is balanced, the sum of the clockwise moments about any point equals the sum of the anticlockwise moments about the same point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Balanced forces

A

Occur when there is no resultant force on an object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Newton’s first law

A

A body stays at rest, or if moving, it continues to make with uniform velocity, unless an unbalanced force makes it behave differently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Unbalanced forces

A

Occur when there is a resultant force causing an acceleration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Mass

A

Measured in KG shows amount of matter in an object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Newtons second law

A

Force = mass x acceleration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Friction

A

A force that always opposes motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Weight

A

Force of gravity on an object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Acceleration of freefall

A

Acceleration of an object towards the surface of the Earth when the only force on it is the gravitational force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Gravitational field strength, g

A

Gravitational force on an object of mass 1 kg close to the surface of a planet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Equation for weight

A

Weight = force of gravity = mass X acceleration due to gravity

W = M x G

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Gravity on the moon

A

1.6 N/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Deep space gravity

A
  • No gravitational pulls
  • G= 0
  • everything is weightless
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What will happen if there is no air resistance?

A
  • The speed of a falling object will increase by 10 m/s every second
  • acceleration = 10 m/s2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Hookes law

A

Extension is directly proportional to the applied load, up to a limit known as the limit of proportionality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens when a body is thrown vertically upwards?

A
  • Motion is opposed by the force of gravity
  • velocity of the body will decrease by 10m/s in each second until it’s vertical velocity = zero
17
Q

Deceleration/retardation

A

Negative acceleration motion as opposed by force of gravity

18
Q

What does hookes law describe?

A

behaviour of metal wires and springs when they are stretched or compressed

19
Q

What is natural length in Hookes law?

A

Length of a spring, when no stretching or compressing forces are applied

20
Q

Extension in hookes law

A

The difference between the stretch length of a spring, and it’s natural length

21
Q

What do elastic materials do when the force is removed?

A

Returns to original length when stretching force is removed

22
Q

What do plastic materials do when the stretching force is removed?

A

Do you not return to original length when the stretching force is removed

23
Q

Hooks law equation

A

F = ke

24
Q

K hooks law equation

A
  • Spring constant
  • N/CM or N/MM
  • equal to gradient of force – extension graph
25
Q

Pressure equation

A

P = F/A

26
Q

Equilibrium

A

equilibrium is a state in which opposing forces or moments are balanced

27
Q

Pressure

A

Force per unit on a surface

28
Q

Centre of gravity

A

centre of gravity is the point through which the entire weight of a body appears to act

29
Q

neutral equilibrium

A

neutral equilibrium is a state in which a slight displacement causes the object neither to move very far from its original position nor return to it le.g. a ball sitting on a bench)

30
Q

unstable equilibrium

A

unstable equilibrium is a state in which a slight displacement causes the object to move a long way from its original position (e.g. a pencil balanced on its end)

31
Q

stable equilibrium

A

stable equilibrium is a state in which a slight displacement causes the object to return to its original position (e.g. a traffic cone standing on its wide base)

32
Q

What is necessary for maximum stability?

A
  • The centre of gravity should be as low as possible.
  • The area of the base should be as large as possible.
33
Q

What is a moment?

A

The moment about a point is the product of a force and it’s perpendicular distance from the point

34
Q

What is an incorrect direction of the moment?

A

Up or down, moments can only be clockwise or anticlockwise

35
Q

Balanced force

A

If the object of stationary it will remain stationary, if it is moving, it will carry on moving at the same speed and in the same direction

36
Q

Unbalanced forces

A

An unbalance force on an object, causes the object accelerate, according to F = MA