Mechanics Flashcards

1
Q

What are the equations of motion? (5)

A
v = u + at
s = ut + 1/2at^2
s = vt - 1/2at^2
v^2 = u^2 + 2as
s = (u + v)t/2
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2
Q

What is the acceleration due to gravity?

A

9.8ms^-2

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3
Q
On a displacement-time graph what does each line mean?
Curved 
Straight inclined 
Horizontal 
Straight inclined in other direction
A

Acceleration
Constant velocity
Stationary
Constant velocity in other direction

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4
Q
On a velocity-time graph what does each line mean?
Curved 
Straight incline 
Horizontal 
Straight inclined in other direction
A

Non-uniform acceleration
Uniform acceleration
Constant velocity
Uniform deceleration

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5
Q

How do you resolve horizontally?

A

ucosx

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6
Q

How do you resolve vertically?

A

usinx

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7
Q

What component remains constant in a projectiles question?

A

Horizontal, neglecting air resistance

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8
Q

How do you solve a projectiles question? (3)

A

Resolve horizontally and vertically
Use the vertical component to work out how long its in the air and how high it goes
Use the horizontal component to work out how far it goes whilst in the air

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9
Q

State Newton’s first law

A

An object will remain in its current state of motion unless acted upon by a resultant force

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10
Q

When is a body said to be in equilibrium?

A

When a number of forces act on a body the vector sum equals zero

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11
Q

What is the centre of mass?

A

The point at which all the mass is concentrated

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12
Q

State Newton’s second law

A

F=ma

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13
Q

State Newton’s third law

A

If body A exerts a force on body B, the body B will exert a force on body A

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14
Q

What are the similarities of Newton’s third law pairs? (4)

A

Type
Act along the same line
Act for the same time
Equal magnitude

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15
Q

What are the differences of Newton’s third law pairs? (2)

A

Act on different bodies

Act in opposite directions

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16
Q

What is the relationship between work and energy?

A

Energy is transferred when work is done on it

17
Q

What is the principle of conservation of energy?

A

Energy cannot be created or destroyed. It can be transferred into other forms
KE=GPE=WD=EPE

18
Q

What is power?

A

The rate of doing work

19
Q

What is the centre of gravity?

A

The point at which the weight of a body may be considered to act

20
Q

What is meant by work done?

A

Force x distance moved in the direction of the applied force

21
Q

When a ball is thrown vertically upwards, at the maximum height what is the acceleration of the ball?

A

-9.8ms^-1

22
Q

Why is it necessary that the maximum mass is not exceeded on a spring? (3)

A

The elastic limit will be exceeded
The spring will not return to its original dimension
The spring constant will change

23
Q

Describe the energy transfers of a bungee jumper

A

GPE -> KE
GPE + KE -> EPE
EPE -> KE + GPE

24
Q

Is force a vector or scalar?

A

Vector

25
Q

What is a resultant force?

A

The sum of all the forces acting on an object

26
Q

Name the stages of a skydiver on the earth

A
  1. First jumps: only force acting is weight
  2. As his velocity increases, the air resistance opposing the motion increases
  3. Air resistance increases until it is equal to weight. At this point there is no acceleration. Terminal velocity
27
Q

Name the stages of a skydiver on the moon

A

Only force acting is weight, due to a lack of atmosphere

28
Q

How many kg in 1 tonne?

A

1000kg

29
Q

What is free fall?

A

An object that falls to the ground with no forces acting on it except gravity

30
Q

Explain the effects of air resistance on a balls motion? (projectiles)

A

The ball will decelerate horizontally because air resistance adds a backwards force

31
Q

For a body to travel at a constant speed, what must the resultant force be equal to?

A

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