PANIC FLASHCARDS PAPER 2
Is air resistance a contact or non-contact force? Explain your answer.
Contact, the air particles are hitting the object
Is power a vector or a scalar? Explain your answer.
scalar, only magnitude and no direction
If an object does return to its original shape after the forces have been removed, it is known as _______ deformation.
On the other hand, if an object does not return to its original shape after the forces have been removed, it is known as _________ deformation (or sometimes plastic deformation).
Elastic
Inelastic
What are the units for moments?
Newton metres (Nm)
Atmospheric pressure is _________ at a higher elevation.
Higher or lower?
Lower
There is greater atmospheric pressure at sea level than at higher elevation. Why is this? (2)
The air is less dense at sea level
There are more gas particles at sea level to collide with objects
The air is more dense at sea level
There are more gas particles at sea level to collide with objects
The air is more dense at sea level
A person is walking 1.5 m/s north.
Is this an example of velocity or speed?
Velocity
What does the gradient of a velocity/time graph tell us?
The acceleration or deceleration of the object
What is Newton’s first law?
A resultant force is required to change the motion of an object.
What is Newton’s second law?
A resultant force will cause an object to accelerate in the direction of the force.
An example of circular motion is the moon orbiting the earth.
Which of the following are true? (2)
The moon is moving with constant velocity
The moon is moving at a constant speed
The moon is accelerating
The moon is not accelerating
The moon is moving at a constant speed
The moon is accelerating
What is Newton’s third law?
When two objects interact, the forces they exert on each other are equal and opposite?
When pushing against a wall, the wall pushes back with an equal and opposite force.
What is this force called?
The normal contact force
A vehicle drives twice as fast.
What happens to the braking distance?
The braking distance increases by four times
What factor affects both the thinking distance and the braking distance?
Speed of the vehicle
The total momentum before a collision is ________ the total momentum after the collision.
Less than / equal to / greater than?
Equal to
Which safety features of a car aim to slow the rate at which momentum is lost? (2)
Crumple zones
Air bags
Safety glass
Turning indicators
Crumple zones
Air bags
Light travelling from a less dense material, into a more dense material, will bend ________ the normal.
towards
When a wave travels into a more dense medium, the wave speed decreases.
What happens to the frequency of the wave?
Stays the same
Which of the following is true of radio waves?
They have a short wavelength, and a high frequency
They have a short wavelength, and a low frequency
They have a long wavelength, and a high frequency
They have a long wavelength, and a low frequency
They have a long wavelength, and a low frequency
What types of electromagnetic waves can be used in communication?
Radio and microwaves
What are the three types of radio waves?
Long, short, very short waves
What type of electromagnetic waves have longer wavelengths?
Visible light / ultraviolet light
Visible light
What can ultraviolet be used for?
Give sun tans
Check for ‘invisible markings’ on passports
Destroy microorganisms in water sterilisation
What does an object’s colour depend on?
Wavelengths of light reflecting off of the object
Wavelengths of light hitting the object
Wavelengths of light absorbed by the object
What happens to the speed of sound waves when they travel from a less dense medium to a more dense medium?
Their speed increases
Put the states of matter in order based on how fast sound waves travel through them (start with fastest)
Solids, liquids, gases
What is the role of the eardrum?
Transmit the vibrations of the sound wave to the ossicles
What is the role of the auditory nerve?
Transmit the electrical signals from the cochlea to the brain
Do P-waves or S-waves travel faster?
P-waves
What are some examples of magnets?
A bar magnet, the Earth, a horseshoe magnet
What elements are magnetic?
Iron, cobalt, nickel
What are magnetic materials that gain and lose magnetism quickly called?
Magnetically soft materials
What are magnetic materials that gain and lose magnetism slowly called?
Magnetically hard materials
Describe the four ways to increase the strength of an electromagnet
Increase current
Increase number of turns in the solenoid, while keeping the length the same
Reduce the length of the solenoid while keeping the number of turns the same
Add a soft iron core
Give three ways to increase the speed of rotation in an electric motor
Add more turns to the coil
Increase magnetic field strength / magnetic flux density of the magnet
Increase the current in the coil
Name the three ways to increase the size of the potential difference generated in electromagnetic induction
Increase magnetic field strength / magnetic flux density
Move the coil through the magnetic field faster
Add more turns to the coil
What is the difference between the design of an alternator and the design of a dynamo?
An alternator has slip rings (and brushes)
A dynamo has a split-ring commutator
Explain how an electromagnetic induction (generator effect) in used in dynamos
A coil of wire is turned inside a magnetic field
This induces a (magnetic field and) current in the coil of wire.
The commutator switches the connections every half-turn.
This causes the current to be in one direction (d.c.).
What happens to the oscillations on an oscilloscope when you increase the speed at which a coil rotates in an alternator?
The amplitude and the frequency both increase
What do loudspeakers rely on? The motor or generator effect?
Motor effect
What does the ratio of turns in the primary and secondary coil affect?
The current and the voltage in the secondary coil
What is a comet mostly made of?
Ice and dust
Once nuclear fusion starts in a protostar, what does it become?
A main sequence star
What stage of a star’s life cycle is the sun currently in?
Main sequence star
It’s important that you know which elements nuclear fusion forms at each stage of a star’s life cycle.
A ____ sequence star only fuses together hydrogen to make ______.
Then in red giants or red _____ giants, nuclear fusion can form heavier elements up to iron on the periodic table.
Elements heavier than iron are formed by __________.
Main
Helium
Super
Supernovas
For a red giant, what happens next in the star’s life cycle?
It becomes a white dwarf and then a black dwarf
What is required for the object to stay in orbit?
The magnitude of the velocity must increase
How many galaxies show a red-shift?
Nearly all
Give one strength and one weakness of the balloon model in representing the idea of an expanding Universe.
Strength - As the balloon expands the dots get further apart, which represents the galaxies moving apart
Weakness 1 - The dots are only on the surface of the balloon, whereas galaxies are throughout the universe
Why do scientists believe in the big bang theory?
Its prediction are supported by observations
What is the unit for spring constant?
N/m
What is proportional to frequency when the wavelength is kept constant?
Wave speed
Why would a student use a low frequency on a signal generator
To make sure the wavelength isn’t too short to measure using a ruler
