2415/10/21
Measurement
Measuring cylinders can be used to measure the volume by measuring the change in
volume, of an irregular shape.
When measuring very small distances, a micrometre screw gauge is the most appropriate
instrument. It can measure distances to the nearest 1/100th of a MM
Density = mass/volume
Clocks and stopwatches are used to measure time, but it is dependant on human reaction
time
It is difficult to get an accurate answer if you are measuring something very small, like the
thickness of paper. Therefore, it is easier to measure the thickness of 100 sheets of paper
and divide by hundred, this is more accurate than just measuring
8/10/21
Speed time graphs
Average speed = distance/time
In physics, speed is usually measured in m/s, if you are travelling at longer distances you
use km/h
The steeper the gradient on a speed time graph, the faster the speed
The velocity of a body is its speed in a certain direction
Acceleration = velocity change/time taken = answer win m/s²
a=(v-u) /t
,v=final velocity
u=initial velocity
t=time in seconds
Deceleration is the same thing except with different numbers
Acceleration is a vector quantity, you have to write down the magnitude and direction
Velocity Time Graphs
An object accelerating has a curved line on a graph.
An object in constant motion or at rest is a straight line on a graph
The area under a velocity time graph represents the difference travelled.
14/10/21
Mass and Weight
Mass cannot change
Weight changes according to gravity
Earth’s gravity is 10 N/kg
A bathroom scale weighs mass in KG
Gravity is an attractive force that affects anything with mass
The force goes both ways, the Earth is attracted to us
Gravity depends on 2 things:
The mass of the object
The distance between the objects
When you double the mass of one object, you double the force
When the distance doubles, the gravitational force divides by 4
The Mass of an object is a measure of how much ‘stuff’ if contains in KG
The Weight of an object is the amount of force that pulls it down due to gravity in Newtons
Weight is mass in gravity
,If the volume increases, the density decreases
, 15/10/21
Effects of Forces
A force is a push or a pull
Force will change the shape or motion of an object
Force is measured in newtons (N)
Forces
❖ Weight
❖ Air resistance (Drag)
❖ Friction
❖ Upthrust
❖ Tension
❖ Thrust
❖ Magnetic Force
❖ Lift
The arrow on force diagrams represent the amount of force, the larger the arrows, the bigger
the force
If the force (Thrust) is bigger than drag, the object accelerates
Forces are measured in Newtons (N)
100g = 1 N
Friction is a force that opposes motion
Friction causes energy to be transferred as heat and causes wearing of mechanical parts
Friction is important in car braking systems as it relies of friction
An unbalanced force can
❖ Change the speed of a body
❖ Change the direction of a body
❖ Change the shape of a body
If zero resultant force acts on an object, it will remain still or move in a straight line at
constant speed
Newton’s First Law
If no resultant force acts on an object, it will remain still or move in a straight line at constant
speed
Force (N) = Mass (Kg) x acceleration (m/s^2)
Measurement
Measuring cylinders can be used to measure the volume by measuring the change in
volume, of an irregular shape.
When measuring very small distances, a micrometre screw gauge is the most appropriate
instrument. It can measure distances to the nearest 1/100th of a MM
Density = mass/volume
Clocks and stopwatches are used to measure time, but it is dependant on human reaction
time
It is difficult to get an accurate answer if you are measuring something very small, like the
thickness of paper. Therefore, it is easier to measure the thickness of 100 sheets of paper
and divide by hundred, this is more accurate than just measuring
8/10/21
Speed time graphs
Average speed = distance/time
In physics, speed is usually measured in m/s, if you are travelling at longer distances you
use km/h
The steeper the gradient on a speed time graph, the faster the speed
The velocity of a body is its speed in a certain direction
Acceleration = velocity change/time taken = answer win m/s²
a=(v-u) /t
,v=final velocity
u=initial velocity
t=time in seconds
Deceleration is the same thing except with different numbers
Acceleration is a vector quantity, you have to write down the magnitude and direction
Velocity Time Graphs
An object accelerating has a curved line on a graph.
An object in constant motion or at rest is a straight line on a graph
The area under a velocity time graph represents the difference travelled.
14/10/21
Mass and Weight
Mass cannot change
Weight changes according to gravity
Earth’s gravity is 10 N/kg
A bathroom scale weighs mass in KG
Gravity is an attractive force that affects anything with mass
The force goes both ways, the Earth is attracted to us
Gravity depends on 2 things:
The mass of the object
The distance between the objects
When you double the mass of one object, you double the force
When the distance doubles, the gravitational force divides by 4
The Mass of an object is a measure of how much ‘stuff’ if contains in KG
The Weight of an object is the amount of force that pulls it down due to gravity in Newtons
Weight is mass in gravity
,If the volume increases, the density decreases
, 15/10/21
Effects of Forces
A force is a push or a pull
Force will change the shape or motion of an object
Force is measured in newtons (N)
Forces
❖ Weight
❖ Air resistance (Drag)
❖ Friction
❖ Upthrust
❖ Tension
❖ Thrust
❖ Magnetic Force
❖ Lift
The arrow on force diagrams represent the amount of force, the larger the arrows, the bigger
the force
If the force (Thrust) is bigger than drag, the object accelerates
Forces are measured in Newtons (N)
100g = 1 N
Friction is a force that opposes motion
Friction causes energy to be transferred as heat and causes wearing of mechanical parts
Friction is important in car braking systems as it relies of friction
An unbalanced force can
❖ Change the speed of a body
❖ Change the direction of a body
❖ Change the shape of a body
If zero resultant force acts on an object, it will remain still or move in a straight line at
constant speed
Newton’s First Law
If no resultant force acts on an object, it will remain still or move in a straight line at constant
speed
Force (N) = Mass (Kg) x acceleration (m/s^2)
