Paper 2 Required practicals Flashcards
Elasticy PAG - Describe a suitable method
Hang a spring off a clamp stand
Measure the original length of the spring
Add a 1 N weigth and measure the final length of the spring with a ruler
Calcualte the extension (final length - original length)
Repeat for weights 2, 3, 4, 5 and 6 N
Elasticy PAG - State the variables and whether they are continuous, discrete or catergoric
Independent - Weight (continuous)
Dependent - Extension (continuous)
Control - Spring constant (continuous)
Elasticy PAG - What type of graph should you draw? Why?
Line - both variables are continuous
Elasticy PAG - Describe the expected results
Forces is directly proportional to extension as long as the elastic limit hasnt been passed.
The graph should be a straight line through the origin up to the elastic limit.
Elasticy PAG - What is the main cause of error and how can it be reduced?
Parallax error not having your eye level with the spring when measuring its extension.
Reduce this my placing a wooden splint horizontally at the bottom of the spring.
Elasticy PAG - Describe a suitable risk assessment
Clamp stand may topple - this could fall and hurt your foot - place a counter weigth on the base of the clamp to stop it toppling
Elasticy PAG - Describe elastically deformed
The object will return to its original length when all forces are removed
Elasticy PAG - Describe inelastically deformed
An object wont return its original length once all forces are removed, it has been permanently stretched.
Elasticy PAG - State Hooke’s law equation
Force (N) = Spring constant (N/m) x extension (m)
Elasticy PAG - how can the spring constant be found from a graph of force against extension
From the gradient
Newton’s second law PAG - state the relevant equation
Resultant Force (N) = mass (kg) x acceleration (m/s2)
Newton’s second law PAG - Describe a suitable method
Attached a piece of card of known length to a trolley.
Attached some string to the trolley running over a pulley.
Place a 1 N weigth on the end of the string and allow it to accelerate the trolley through two light gates.
Use the light gates to measure the acceleration of the trolley
Repeat for 2, 3, 4, 5 and 6 N
Newton’s second law PAG - State the variables and whether they are continuous, discrete or catergoric
Independent - Resultant force (continuous)
Dependent - Acceleration (continuous)
Control - mass of trolley (continuous), Material of surface (discrete)
Newton’s second law PAG - State the expected results
As resultant force increases the acceleration will increase. They are directly proportional to each other so the graph should be a straight line through the origin.
Newton’s second law PAG - Describe a risk assessment
Falling masses - could land on your feet - stand away from the experiment
Newton’s second law PAG - If the resultant force was kept constant but the mass of the trolley was increased what results would you expect?
As mass of the trolley increases the acceleration will decrease, they are inversley proportional to each other.
Newton’s second law PAG - What type of graph should you draw? Why?
Line - both variables are continuous
Newton’s second law PAG - How can a light gate measure velocity?
Tell the data loger the length of card (distance)
The light gate will measure the time the card blocks the laser.
Velocity = distance / time
Newton’s second law PAG - How can two light gate measure acceleration?
Light gate 1 measures initial velocity
Light gate 2 measures final velocity
Light gate measure the time between light gates
acceleration = change in velocity / time
Reflection and refraction PAG - Describe the law of reflection
The angle of incidence = the angle of reflection for a flat plain mirror
Reflection and refraction PAG - Describe refraction
The changing of direction of a wave as it enteres a new material.
Reflection and refraction PAG - Why does refraction take place?
The new material has a different density so causes a change in speed.
Reflection and refraction PAG - When will a wave refract towards the normal?
When the wave slows down
Reflection and refraction PAG - When will a wave refract away from the normal?
When the wave speeds up
Reflection and refraction PAG - If a wave moves from air into glass how are the following effected?
Speed
Wavelength
Frequency
Speed - slows down
Wavelength - decreases
Frequency - stays the same
Reflection and refraction PAG - If a wave moves from glass into air how are the following effected?
Speed
Wavelength
Frequency
Speed - increases
Wavelength - increases
Frequency - stays the same
Reflection and refraction PAG - What are the main sources of error and how can they be reduced?
The beam of light spreads out so it is hard to judge the centre of the ray of light.
Use a laser and repeat readings
Reflection and refraction PAG - What are the main sources of risk?
The bulb will get hot - this could burn - turn off and let it cool down before moving it
Wave measurments (Ripple tank) PAG - Describe how the speed of water waves can be found using a ripple tank
Measure the wavelength using a ruler. Measure across as many waves as possible. Divide the total length by the number of waves.
Measure the frequency using a stop watch. Time for 10 seconds and count how many waves pass a point. Divide the number of waves by 10 seconds to find the frequency.
Calcualte the wave speed using the equation
Speed (m/s) = Frequency (Hz) x Wavlength
Wave measurments (Standing waves) PAG - Describe how to calcualte the speed of standing waves.
Record the frequency off the signal generator.
Measure the wavelength with a meter ruler. To make this more accurate measure as many wavelengths as possible and divide the total length by the number of wavelengths.
Calcualte the wave speed using the equation
Speed (m/s) = Frequency (Hz) x Wavlength
