Physics Paper 2 Flashcards
What is a contact force and what are some examples?
When two objects have to be touching for a force to act (e.g friction and air resistance).
What is a non-contact force and what are some examples?
When two objects don’t have to be touching for the force to act (e.g magnetic force, gravitational and electrostatic).
What is the connection between weight and mass?
Weight and mass are directly proportional.
What are the 8 energy stores?
- Thermal
- Kinetic
- Chemical
- Magnetic
- Nuclear
- Electrostatic
- Elastic potential
- Gravitational potential
What is a closed system?
Systems where matter nor energy can enter or leave, the net change in the total energy is always zero.
What is resultant force?
Overall force on a point or object.
What is equilibrium?
If all of the forces acting on an object combine to give a resultant force of zero.
What is displacement?
Measures the distance and direction in a straight line from an objects start to finish points.
What is a scalar quantity?
Measurement with no real direction (e.g Distance and Speed).
What is a vector quantity?
Measurement with a specific direction (velocity and displacement).
What is deceleration?
Negative acceleration (slowing down).
What is uniform acceleration?
Constant acceleration.
What is terminal velocity?
The maximum sleed of an object (it will then travel at a constant speed).
What is Newtons 1st law?
A force is needed to change motion. This means if the resultant force on a stationary object is zero, it will remain stationary. This will also mean if the resultant force on a moving object os zero, it will carry on moving at the same velocity.
What is Newtons 2nd law?
Acceleration is proportional to the resultant force. Acceleration is also inversly proportional to the mass of an object.
What is inertia?
The tendency for motion to remain unchanged.
What is Newtons 3rd law?
When two objects interact, the forces they exert on each other are equal and opposite.
What is optical density?
How quickly light can travel through it, the higher the optical density, the slower light waves travel through it.
Why can Long-wave radio travel over lomg distances?
They can diffract (bend) around the curved surface of the earth.
Why can short-wave radio be recieved over lomg distances?
They are reflected fom the ionosphere.
How are microwaves used?
- Used for communication to and from satellites.
- Heat up food by the watermolecules absorbing the energy from the waves and then transferring it the rest of the food.
How is infared radiation used?
- Infrared cameras can be used to detect and monitor temperature.
- The camera turns the IR into an electrical signal and it is displayed on a screen.
What are optical fibres?
Thin glass or plastic fibres that carry data over long distances as pulses of visible light. The light rays bounce back and forth until they reach the end of the fibres.
What are the dangers of UV radiation?
- Sunburn
- Skin to age prematurely
- Blindness
- Skin cancer
What are the dangers of X-rays and Gamma rays?
- Cell destruction
- Gene mutation
- Cause Cancer
What is radiation dose?
Measure of the risk of harm from the body being exposed to radiation. It is measured in sieverts.
How do you increase the strength of a magnetic field?
By wrapping the wire into a coil called a solenoid.
What is the motor effect?
When a current-carrying wire is put between magnetic poles, the magnetic field around the wire interacts with the magnetic field it has been placed in. This causes the magnet and the conductor to exert a force on each other.
