Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A-Level Physics > Physics 4 - Mechanics and Materials > Flashcards

Physics 4 - Mechanics and Materials Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

What is a scalar quantity?

A

A quantity that has only magnitude.

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

What is a vector quantity?

A

A quantity that has both magnitude and direction.

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

Is acceleration a vector or a scalar quantity?

A

Vector.

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

Is mass a scalar or vector quantity?

A

Scalar.

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

What is the difference between mass and weight?

A

Mass is scalar and independent of the gravity acting upon it. Weight is a vector and depends on the gravitational field strength.
W=mg

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

Describe the principal of moments.

A

For an object in equilibrium; the sum of clockwise moments is equal to the sum of anticlockwise moments.

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

What does it mean for an object to be in equilibrium?

A

It is not accelerating, so it is either stationary or moving at a constant velocity.

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

How can the forces acting on an object be shown to be in equilibrium?

A

Adding the horizontal and vertical components of the forces acting on it, showing that they equal zero.
Or, if there are 3 forces acting on the object, you can draw a scale diagram, if the scale diagram forms a closed triangle, the object is at equilibrium.

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

What is a moment?

A

A turning force; the force multiplied by the perpendicular distance from the point to the line of action of the force.

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

What is meant by a couple?

A

A pair of equal and opposite coplanar forces.

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

What is meant by the centre of mass?

A

The point through which all the mass of an object acts for a uniform object the centre of mass is the centre of the object.

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

If you have a uniform object, where would its centre of mass be?

A

At the centre of the solid.

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

What is velocity?

A

The change in displacement per unit time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the gradient of a displacement-time graph?

A

The instantaneous velocity at that time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the area under a velocity time graph?

A

The displacement travelled.

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

What is the gradient of a velocity-time graph?

A

The acceleration at that time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the area under an acceleration-time graph?

A

The velocity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens to air resistance as speed increases?

A

It increases too, proportionally to the square of the speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

A ball is projected off of a castle wall at 6m/s, how does its horizontal velocity change from its launch until it hits the ground?

A

The horizontal velocity remains the same as there is no acceleration in that direction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do the SUVAT equations reflect that all objects fall at the same rate?

A

Mass is not included in the SUVAT equations, showing that the mass of an object doesn’t affect its speed or acceleration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

In projectile motion, what is the vertical acceleration?

A

The vertical acceleration is equal to gravitational field strength (g).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is meant by terminal velocity?

A

When the forces acting on an object become balanced, the acceleration becomes zero and the object is moving at maximum velocity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is meant by friction?

A

A resistance to motion between an object and a surface or an object moving through a fluid. Friction is a force that acts in the opposite direction to the movement.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is Newton’s third law?

A

Every action force has an equal and opposite reaction force.

25
Q

What is Newton’s second law?

A 
F=ma
Where;
F=Force applied
m=Mass (which remains constant
a=Acceleration
26
Q

What is Newton’s first law?

A

An object stays moving at a constant velocity until a force acts upon it.

27
Q

What is the difference between elastic and inelastic collisions?

A

In an elastic collision the kinetic energy before is equal to the kinetic energy afterwards.
In an inelastic collision the kinetic energy at the end is not equal to the kinetic energy at the start.

28
Q

Give an equation that can be used to calculate momentum.

A

momentum=mass×velocity

29
Q

True or false: “Linear momentum is only conserved in elastic collisions.”?

A

False, linear momentum is always conserved.

30
Q

What is force?

A

The rate of change of momentum.

31
Q

What is impulse?

A 
The change in momentum.
FΔt=Δ(mv)
Where:
F=Force
Δt=Change in time
Δ(mv)=Change in momentum
32
Q

What does the area underneath a force-time graph represent?

A

Impulse, the change in momentum.

33
Q

What is work done moving an object?

A 
W=F×s×cos(θ)
Where:
W=Work done
F=Force
s=Displacement
θ=Direction of force
34
Q

What’s the rate of work done equal to?

A

The power.

35
Q

What is efficiency?

A

Efficiency=Useful output power/Input power

36
Q

What is meant by the principal of conservation of energy?

A

Energy cannot be created or destroyed, only transferred into other forms of energy.
Therefore the total energy in a closed system will always remain the same.

37
Q

What is lift?

A

An upward force which acts on objects travelling in a fluid, it is caused by the object creating a change in direction of fluid flow and acts perpendicular to the direction of fluid flow.

38
Q

What is Hooke’s law?

A 
Extension is directly proportional to the force applied, given that the environmental conditions are kept constant.
F=kΔL
Where;
F=Force applies (N)
k=Stiffness constant (Nm⁻¹)
ΔL=Extension (m)
39
Q

What equation is used to calculate density?

A 
ρ=m/V
Where:
ρ=Density (kgm⁻³)
m=Mass (kg)
V=Volume (m³)
40
Q

What is meant by tensile stress?

A 
The force applied per unit cross sectional area.
Stress=f/A
Where:
Stress (Nm⁻²)
f=Force (N)
A=Cross sectional area (m²)
41
Q

What is tensile strain?

A 
A measure of how the material stretches; the extension divided by the original length strain has no units.
Strain=ΔL/L
Where:
Strain (no units)
ΔL=Extension (m)
L=Original length (m)
42
Q

What is the difference between elastic and plastic deformation?

A

Elastic deformation is where, when the force is removed, the object will return to its original dimensions.
Plastic deformation is where, when the force is removed, the object will not return to its original dimensions.

43
Q

What is breaking stress?

A

The minimum stress needed to break a material.

44
Q

What is meant by brittle?

A

It doesn’t deform plastically but breaks when stress reaches a certain value.

45
Q

What is the elastic limit?

A

The force above which the material will be plastically deformed (permanently stretched).

46
Q

What is the area underneath a force-extension graph?

A 
The work done to deform the material.
Work done=½FΔL
Where:
Work done (J)
F=Force deforming the object
ΔL=Deformation
47
Q

State the equation to calculate elastic strain energy from the spring constant and extension.

A

E=½kΔL²
E=Energy (J)
k=Spring constant (Nm⁻¹)
ΔL=Extension (m)

48
Q

What is the Young modulus?

A 
A description of the stiffness of a material.
Young modulus =tensile stress/tensile strain
E=FL/ΔLA
Where:
E=Young modulus (Nm⁻²)
F=Force (N)
L=Original length (m)
ΔL=Extension (m)
A=Cross sectional area (m²)
49
Q

How would you find the Young modulus from a stress-strain graph?

A

The gradient of the line.

50
Q

How can a force-extension graph show Hooke’s Law is being obeyed?

A

When it is a straight line through the origin, so force and extension are directly proportional.

51
Q

What is the limit of proportionality and what does it look like on a force-extension graph?

A

The point after which Hooke’s law is no longer obeyed, it is shown by the line beginning to curve on a force-extension graph.

52
Q

How is the work done to stretch or compress a material stored?

A

Elastic strain energy.

53
Q

Why are the loading and unloading lines parallel on a force-extension graph for a plastically deformed material?

A

The stiffness constant (k) hasn’t changed, the force between the atoms are the same when loading and unloading.

54
Q

Why isn’t all work done stored as elastic strain energy when a stretch is plastic?

A

Work is done to move atoms apart, so energy is not stored as elastic strain energy but is dissipated as heat.

55
Q

How is the dissipation of energy in plastic deformation used to design safer vehicles?

A

Crumple zones deform plastically in a crash using the car’s kinetic energy so less is transferred to the passengers.
Seat belts stretch to convert the passenger’s kinetic energy into elastic strain energy.

56
Q

Outline the energy changes that occur when a spring fixed at the top is pulled down and released.

A

The work done in pulling the spring down (stretching it) is stored as elastic strain energy, when the spring is released this is converted to kinetic energy which is converted to gravitational potential energy as the spring rises.

57
Q

Do stress-strain graphs show the behaviour of a material or a specific object?

A

Material.

58
Q

Where would you find the ultimate tensile stress on a stress-strain graph?

A

The highest point on a graph, it is the maximum stress a material can withstand.

59
Q

What would the stress-strain graph for a ductile material look like?

A

A ductile material can undergo a large amount of plastic deformation before fracturing.

A-Level Physics (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions