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74 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What does physical quantity mean? |
Anything we can measure. |
Measuring |
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What are the two types of physical quantities? |
Scalar and Vector |
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What is a scalar |
Magnitude (size) only, distance. |
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What is a vector? |
Magnitude and direction, displacement |
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Give two examples of a scalar |
Mass and time. |
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Give two examples of a vector. |
Force(N), Velocity forwards |
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What is the equation for average speed? |
Average speed = Distance travelled ÷ Time taken |
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What is the equation for average velocity? |
Average velocity = Displacement ÷ Time |
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What do you need to consider to find the instantaneous speed of an object? |
The shortest period of time possible, how far the object travels over this time. |
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What is the equation for average acceleration? |
Average Acceleration = (Final - Initial Velocity) ÷ Time |
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What is the unit for acceleration? |
M/s^2 |
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What is the difference between distance and displacement time graphs? |
Distance time graphs are always positive. |
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What does the gradient show in a displacement time graph? |
Velocity. |
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What does the horizontal line show in a displacement time graph? |
That it is stationary. |
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What does an increasing gradient mean in a displacement time graph? |
It is accelerating |
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What does a decreasing gradient mean in a displacement time graph? |
That is is decelerating. |
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What does the gradient show in a velocity time graph? |
It is accelerating |
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What does the area show in a velocity-time graph? |
Displacement |
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What does a constant gradient show in a velocity-time graph? |
Constant acceleration. |
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What does a flat line show when it is at 0 and not at zero in a velocity time graph. |
At 0 it shows it is at rest and when it is not at zero it is at a constant speed. |
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What does a positive constant gradient show when it is at 0 and not at 0 in a velocity time graph? |
When it is at 0 it is a constant acceleration forwards when it is not at 0 it's a constant deceleration backwards. |
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What does a negative constant gradient show when it is at zero and when it is not at zero in a velocity time graph? |
When it is at 0, deceleration, when it is not at 0 it is acceleration backwards |
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What is the definition of resultant force? |
A single force that represents all forces on an object. |
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What is Newtons first law? |
If the resultant force = 0 then motion remains constant. |
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What is Newtons second law? |
The resultant forces not at zero, object accelerates. The acceleration is directly proportional to the resultant force. F = ma. |
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What can all substances be classified into? |
Conductors and insulators. |
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What is the definition of electrical conductors? |
The materials which allow electric current to pass through easily. |
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Give an example of an electrical conductor. |
Metals. |
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What is the definition of electrical insulators? |
Matters which do not allow electric current to pass through easily. |
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Give two examples of electrical insulators. |
Wood and plastic |
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What is Boyle's law? |
Pressure is inversely proportional to volume PV = k, for a given amount of gas at each temperature. When there is a decrease in volume there is always a particle separation then the frequency of collisions rises this increases the force per unit area making increase of pressure. |
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What is an advantage of a series circuit? |
Uses less wired in a parallel circuit. |
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Show the VI graph for a fixed resistor |
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What is the equation for power with potential difference and current? |
P = VI. V = potential difference, I = current |
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What is the equation for voltage? |
V = i x r. I is current, r is resistance. |
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What is the definition for power? |
The rate at which energy is transferred. |
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What is the equation for power with time and energy transfer? |
Power = energy transfer ÷ time |
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What is the unit for power? |
W / whatt |
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What's the equation for charge? |
Q = i x t |
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What is a disadvantage of a series circuit? |
You have no independent control of components |
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What is a disadvantage of a series circuit? |
If one component fails the whole circuit breakes |
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What is one use of a series circuit? |
Christmas tree lights |
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What are two uses of parallel circuits? |
Car headlamps. Lies and appliances in your home |
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What is a disadvantage of a parallel circuit? |
It uses more wires than a series circuit |
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What is an advantage of a parallel circuit? |
Yes control over each component |
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What is one advantage of a parallel circuit? |
Even if one component fails the rest of the circuit still works |
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What is refraction? |
Waves change speed when they go get to a substance of different optical density.light slows down in more optically dense substances. Light speeds up in less optically dense substances. Due to this we sometimes observed the light change direction. |
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Why don't protons repel against each other? |
They are held together by neutrons |
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What is radioactive decay? |
If a nucleus is unstable it's gives out radiation to try and become stable |
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Give two dangers of ionising radiation |
It can cause DNA to mutate, abnormal cell growth leading to cancer |
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What is a becquerel? |
One decay per second |
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What is count rate? |
Count rate is the number of decays recorded by the detector. |
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What is a radiation? |
The process of exposing an object to nuclear radiation |
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Does the irradiated object become radioactive? |
No |
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Give two examples of a irradiation |
Having an X-ray, taking a long-haul flight |
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What is radioactive contamination? |
It is from the unwanted presence of materials containing radioactive nuclei |
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What is the Hazard? |
Issues from the alpha, beta and gamma being emitted by the contaminating of atoms |
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What does the level of contamination depend on? |
The type of radiation being emitted |
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What is half life? |
It is the amount of time it takes for half the radioactive nuclei to decay, the activity to half and the count rate to half |
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How do you find the half-life from a decay curve? |
You find the largest point on the curve. Have it and draw a dotted line from the hob number to the line. Look at the x-axis to find the half-life |
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What does the activity depend on? |
How unstable the radioactive isotope is, how many unstable nuclei there are |
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What happens when you destroy mass? |
If you destroy a tiny amount of mass you make a lot of energy. |
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What are the uses of nuclear reactions? |
Nuclear bombs and nuclear power stations |
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What are the two types of nuclear reactions? |
Fission and fusion |
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What is fission? |
The splitting of a large parent nucleus into smaller nuclei destroying mass which produces energy |
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What is Fusion? |
Why you fuse two small nuclei to create a larger nucleus, some mass is converted into energy |
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How do you control fission? |
You absorb neutrons |
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For the nuclei to collide, what must they improve? |
Electrostatic repulsion. This requires very high temperatures. |
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What is the equation for work done? |
Work done = force x distance |
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What is the relationship between energy transfered, current, voltage and time. |
Energy transfered = current x voltage x time |
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What is the relationship between power, current and voltage? |
Power = current x voltage |
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What is the difference between a.c and d.c? |
A.c changes where the charges switch places whilst in d.c the charges don't stay in the same flow |
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What is the equation for weight? |
Weight = mass x gravitational field strength |
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What is the stopping distance made up of? |
Sum of thinking distance + the braking distance |
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