A Level Physics: Mechanics and Materials

studied byStudied by 1 Person
0.0(0)
Get a hint
hint

What is a scalar quantity?

1/178

Tags & Description

Studying Progress

New cards
178
Still learning
0
Almost done
0
Mastered
0
178 Terms
New cards

What is a scalar quantity?

Something with only magnitude

New cards
New cards

What is a vector quantity?

Something with magnitude and direction

New cards
New cards

Give 6 examples of scalar quantities.

Mass, temperature, time, distance, speed and energy

New cards
New cards

Give 5 examples of vector quantities.

Displacement, velocity, force, acceleration and momentum

New cards
New cards

When resolving, the horizontal component is always ...

... xcosθ

New cards
New cards

When resolving, the vertical component is always ...

... xsinθ

New cards
New cards

A body in equilibrium can be ...

... at rest or moving with a constant velocity

New cards
New cards

If a closed loop triangle can be drawn with 3 coplanar forces, what does it say about the body?

That it is in equilibrium

New cards
New cards

Why can the vertical component here be ignored?

P has no vertical component so the other forces must cancel the vertical component out because the body is in equilibrium

New cards
New cards

What is a moment?

The product of the force and the perpendicular distance from the point to the line of action of the force

New cards
New cards

M =

F x d

New cards
New cards

What is the principle of moments?

For the body to be in equilibrium, the sum of the clockwise moments about any point equals the sum of the anticlockwise moments

New cards
New cards

What is a couple?

A pair of forces of equal size which act parallel to each other, but in opposite directions

New cards
New cards

How do you calculate the moment of a couple?

The magnitude of one force x the perpendicular distance between the lines of action of the forces

New cards
New cards

What are the units for a moment?

Nm

New cards
New cards

What is inertia?

An object's resistance to a change in velocity

New cards
New cards

What is weight?

The force experienced by a mass due to a gravitational field

New cards
New cards

w =

m x g

New cards
New cards

What are the units for gravity?

Nkg^-1

New cards
New cards

What is the centre of mass of an object?

The point through which a single force on the body has no turning effect and where its whole weight can be considered to act through

New cards
New cards

How can you fin the centre of mass via experiment?

  1. Hang an object freely from a point 2. Draw a vertical line downwards from the point of suspension, using a plumb bob 3. Hang the object from another point and repeat 4. Where these two lines cross is the centre of mass

New cards
New cards

An object will topple over if a vertical line drawn downwards from its centre of mass ...

... falls outside its base area, due to a resultant moment providing a turning force

New cards
New cards

An object will be more stable if it has ...

... a low centre of mass and wide base area

New cards
New cards

What is displacement?

How far an object has travelled from its starting point in a given direction

New cards
New cards

What is velocity?

The rate of change of an object's displacement

New cards
New cards

What is acceleration?

THe rate of change of an object's velocity

New cards
New cards

velocity =

s/t

New cards
New cards

acceleration =

v/t

New cards
New cards

What is the name of the speed of an object at a given point in time?

Instantaneous speed

New cards
New cards

How do you find the average speed or velocity?

Divide the total displacement by the total time

New cards
New cards

For a displacement-time graph, how would an accelerating object be shown?

Curved

New cards
New cards

If the object is accelerating at a uniform rate, the rate of change of the gradient will be ...

... constant

New cards
<p>What kind of acceleration does the displacement-time graph show?</p>
New cards
<p>What kind of acceleration does the displacement-time graph show?</p>

What kind of acceleration does the displacement-time graph show?

Big acceleration

New cards
<p>What kind of acceleration does the displacement-time graph show?</p>
New cards
<p>What kind of acceleration does the displacement-time graph show?</p>

What kind of acceleration does the displacement-time graph show?

Small acceleration

New cards
<p>What kind of acceleration does the displacement-time graph show?</p>
New cards
<p>What kind of acceleration does the displacement-time graph show?</p>

What kind of acceleration does the displacement-time graph show?

Deceleration

New cards
New cards

How can you tell if the velocity is constant on a displacement-time graph?

The graph is a straight line

New cards
New cards

What is the gradient of a displacement-time graph?

The velocity

New cards
New cards

What does it mean if, in a velocity-time graph, the graph becomes negative?

The object is travelling in the opposite direction

New cards
New cards

What is the gradient of a velocity-time graph?

The acceleration

New cards
<p>What kind of acceleration does the velocity-time graph show?</p>
New cards
<p>What kind of acceleration does the velocity-time graph show?</p>

What kind of acceleration does the velocity-time graph show?

Large acceleration

New cards
<p>What kind of acceleration does the velocity-time graph show?</p>
New cards
<p>What kind of acceleration does the velocity-time graph show?</p>

What kind of acceleration does the velocity-time graph show?

Decreasing accleration

New cards
<p>What kind of acceleration does the velocity-time graph show?</p>
New cards
<p>What kind of acceleration does the velocity-time graph show?</p>

What kind of acceleration does the velocity-time graph show?

Increasing acceleration

New cards
<p>What kind of acceleration does the velocity-time graph show?</p>
New cards
<p>What kind of acceleration does the velocity-time graph show?</p>

What kind of acceleration does the velocity-time graph show?

Small acceleration

New cards
New cards

What is the are under a velocity-time graph?

The displacement

New cards
<p>The velocity-time graph shows a ball being dropped and bouncing twice. What is happening here?</p>
New cards
<p>The velocity-time graph shows a ball being dropped and bouncing twice. What is happening here?</p>

The velocity-time graph shows a ball being dropped and bouncing twice. What is happening here?

Ball hits the floor

New cards
<p>The velocity-time graph shows a ball being dropped and bouncing twice. What is happening here?</p>
New cards
<p>The velocity-time graph shows a ball being dropped and bouncing twice. What is happening here?</p>

The velocity-time graph shows a ball being dropped and bouncing twice. What is happening here?

Ball rebounds

New cards
<p>The velocity-time graph shows a ball being dropped and bouncing twice. What is happening here?</p>
New cards
<p>The velocity-time graph shows a ball being dropped and bouncing twice. What is happening here?</p>

The velocity-time graph shows a ball being dropped and bouncing twice. What is happening here?

Top of bounce

New cards
New cards

What is the area under an acceleration-time graph?

The change in velocity

New cards
New cards

On an acceleration-time graph, if a = 0, what does it mean?

The object is moving at constant velocity

New cards
New cards

On an acceleration-time graph, if the acceleration becomes negative, what does it mean?

The object is decelerating

New cards
New cards

Give 3 advantages of using a data-logger to track motion compared to traditional methods like a stopwatch.

  1. Data is more accurate as you don't have to account for human reaction times 2. Automatic systems have a much higher sampling rate than humans 3. You can see data displayed in real time

New cards
New cards

u +at =

v

New cards
New cards

(u+v)/2 x t =

s

New cards
New cards

ut + at^2/2 =

s

New cards
New cards

u^2 + 2as =

v^2

New cards
New cards

What is free fall?

The motion of an object undergoing an acceleration of 'g'

New cards
New cards

What is the only force acting on an object in free fall?

It's weight

New cards
New cards

All objects in free fall ...

... accelerate at the same rate

New cards
New cards

Describe a method to calcutlate g.

  1. Set up a vertical electric circuit with a switch, timer, electromagnet and trapdoor and attach a ball bearing to the electromagnet 2. Measure the h from the ball bearing to the trapdoor 3. Flick the switch to start the timer and disconnect the electromagnet 4. The ball will fall and knock the trapdoor down, breaking the circuit which stops the timer- record this time 5. Repeat 3 times and find an average, then repeat at different h 6. Plot a graph of h against t^2 to find 1/2g as the gradient

New cards
New cards

In an experiment to calculate g, why is it best to use a small and heavy ball bearing?

Air resistance will be so small, it can be ignored

New cards
New cards

In an experiment to calculate g, why is it best to have a computer automatically release and time the ball bearing's fall?

There will be a smaller uncertainty than with human reaction time

New cards
New cards

In an experiment to calculate g, where will the largest source of error come from?

Measuring h as the ruler will have an uncertainty of +/- 1 mm which is much larger than any error from switch delay or air resistance

New cards
New cards

How would you find g on a displacement-time graph?

By finding the change in gradient between two points because a = v / t

New cards
New cards

Which parts of SUVAT can be predicted if an object is falling?

u = 0 a = -9.81

New cards
New cards

Which parts of SUVAT can be predicted if an object is thrown upwards?

u is not 0 a = -9.81

New cards
New cards

Which parts of SUVAT can be predicted if an object is thrown downwards?

u is not 0 a = -9.81

New cards
New cards

Which parts of SUVAT can be predicted if an object is thrown horizontally?

Vertical u = 0 a = -9.81 Horizontal a = 0 u = constant

New cards
New cards

Which parts of SUVAT can be predicted if an object is projected at an angle?

Vertical a = -9.81 Half way through v = 0

New cards
New cards

What is Newton's 1st law?

The velocity of an object will not change unless a resultant force acts on it

New cards
New cards

What is Newton's 2st law in words?

Acceleration is proportional to force

New cards
New cards

What is Newton's 2nd law as an equation?

F = ma

New cards
New cards

What is the resultant force?

The vector sum of all the forces

New cards
New cards

In which direction is acceleration always measured in?

The same as the resultant force

New cards
New cards

Prove that all objects fall at the same rate, regardless of mass using Newton's 2nd Law.

F = ma. Ignoring air resistance, weight is the only force acting on the object so W = F = mg = ma. The two masses cancel out so g = a and g is a constant for a uniform gravitational field

New cards
New cards

What is Newton's 3rd law?

When two objects interact, they exert equal and opposite forces on each other

New cards
New cards

In Newton's 3rd law, the two forces must be equal, opposite and ...

... the same type, like both gravitational or electrical

New cards
New cards

What are the two main types of friction?

Dry friction and fluid friction

New cards
New cards

What does the force of fluid friction depend on?

The viscosity of the fluid

New cards
New cards

As speed increases, fluid friction ...

... also increases

New cards
New cards

The larger the area pushing against the fluid ...

... the greater the resistance force

New cards
New cards

Frictional forces always act ...

... in the opposite direction to the motion of the object

New cards
New cards

Frictional forces can never ...

... speed things up or start something moving

New cards
New cards

Frictional forces convert kinetic energy into ...

... heat and sound

New cards
New cards

What is lift?

An upwards force on an object moving through a fluid

New cards