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Physics P2 Rev
Question | Answer |
---|---|
What is a force? | Can cause change to shape or movement of an object |
What does a slope mean on a distance/time graph? | Steady speed/Accelerating |
What does a straight flat line mean on a distance/time graph? | Stopped |
On a distance/time graph GRADIENT= | Speed |
On a velocity/time graph a sloping line up means | Acceleration |
On a velocity/time graph a flat line means | Steady Speed |
On a velocity/time graph a line along the bottom axis means | Stopped |
On a velocity/time graph a sloping line down means | Decelerating |
On a velocity/time graph GRADIENT= | Acceleration |
What is terminal velocity | When you fall through a fluid and there is a frictional force (drag) |
What is acceleration | When an objects velocity changes |
Pull forces are always | Equal and opposite to eachother as they increase |
Extension of a spring is | Directly Proportional |
Extension of an elastic band is | Not directly Proportional |
Speed- | Distance divided by time |
Regenerative Braking systems... | Uses system that drives the vehicle to do the majority of the breaking. Puts the vehicle in reverse |
Air Bags... | Slow you down more gradually to prevent you from hitting hard surfaces inside the car |
Crumple Zones... | Crumple on impact as kinetic energy is converted into other typed of energe by the car body as the shape changes. It increases the impact times. |
Side Impact Bars... | Direct kinetic energy of crash away from passengers |
Seat Belts... | Increases time for the wearer to stop and reduces the forces in the chest |
What is Momentum? | The property of moving objects |
Momentum before= | Momentum after |
The current in a circuit depends on | The resistance of the components and the supply (Amps) |
What is potential difference? | The driving force that pushes the current around the circuit |
How is static electricity made? | By rubbing 2 different non conductors together |
In static electricity which electrons move? | Negative |
If a material gains electrons... | It becomes negatively charged |
In series circuits potential difference is... | Shared |
In series circuits current is... | The same everywhere |
In series circuits cell voltages... | Add up |
In Parallel circuits potential difference is... | The same everywhere |
In Parallel circuits current is... | Shared between branches |
What is direct current? | Cells and batteries supply current that always passes in the same direction |
What is alternating current? | Current that is constantly changing direction |
How many cycles are there per minute in mains electricity | 50 |
Blue cable is | Neutral |
Brown cable is | Live |
Green and yellow cable is | Earth |
What is a circuit breaker? | An electrical device that protects the circuit from damage if too much current flows |
What is the function of a fuse? | When the current in a fuse wire exceeds the rating of the fuse it will melt so breaks the circuit |
The nucleus in the plum pudding model... | Is tiny and makes up most of the mass of the atom because it contains protons and neutrons so has a positive charge |
The majority of an atom is | Mostly empty space |
Negative electrons... | move around the nucleus really fast which gives it it's overall size |
Alpha radiation... | has 2 protons and 2 neutrons so is a helium nucleus. They are big, heavy and slow moving and are stopped by almost any material |
Beta radiation... | Are quite fast and small and have a long range. They are electrons with a charge of -1. |
Gamma radiation... | Penetrate far into materials and have no mass or charge as they are EM waves |
What is half life? | The average time it takes for the number of nuclei in the isotope in a sample to halve |
What is fission | When the nuclei SPLITS into 2 smaller nuclei and 2 or 3 neutrons and releases energy |
What are the 2 fissionable substances? | Uranium-235 and Plutonium-239 |
What is fusion? | The joining of 2 atomic nuclei to form a larger one. It is the process in which energy is released in stars |