2018 Paper 2 Flashcards
What does an upward straight line on a velocity time graph show
Uniform acceleration
How to tell if something is directly proportional using graph
It will be a straight line passing through origin
Give a source of inaccuracy of ruler spring test
Not fixing ruler to a clamp stand and just holding it
How to find frequency from a graph showing waves
Count number of waves ( count peaks)
Divide this number by time
Explain why study of seismic waves provides evidence for the structure of the earths core
S waves can’t travel through liquid. S waves don’t travel through core wich means the core must be liquid
Explain why the further a swimmer dives, the greater the pressure on the swimmer.
Increased depth means there is more mass above the swimmer so there is greater weight
When a ball hits the ground, energy is transferred from ball to earth. Explain how graph shows this
Velocity just after bounce is less than just before bounce so ball has lost kinetic energy
Sometimes an old scientific model is replaced by a new model.
Explain why scientists replace an old scientific model with a new model. Include an example from Physics in your answe
New experimental data emerges so evidence cannot be explained using existing model so new model explains new evidence as predictions are shown to be correct. Eg: nuclear model replacing the plum pudding model
Explain why refraction happens at the boundary of deep water and shallow water
Velocity is slower in shallow water so edge of wave front entering shallow water slows down but the part of the wave front in deeper water continues at a high speed
When there is a current in the coil, coil rotates continuously. Explain why (motor effect)
Current passes through coil
Current creates a magnetic field. Magnetic field interacts with magnetic feild of permanent magnet
This causes a force of the coil
Therefore the force causes coil to rotate
Two halves of the commutator swap from one carbon brush to the other every half turn wich reverses the current to keep the coil rotating in the same direction
How to draw a vector diagram when they give you the horizontal and vertical lenghts
choose a suitable scale
draw the horizontal and vertical lengths at right angles to each other (make sure to add arrows at the end of each line
(optional helpful step) - add lines from the end of each arrows to create a rectangular box
from the bottom left corner to top right corner draw a straight line
measure the line
measure the line
measure the angle the line makes with horizontal (must state the angle is at horizontal)
BOTH length of line and angle are your answers
how to draw a vector diagram when they give you the magnitude of a single force and angle and want you to work out resultant force ( resolving forces)
choose a scale
draw random horizontal line of any length
draw the angle they give you with a length of the force for “hypotenuse”
draw a vertical straight line to make a right angle triangle - measure length or original base line now that there is a verticsl line attached above it
measure vertical force
do transverse waves need mediums to travel through
no - longitudinal do though
