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42 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What does the gradient of a distant-time graph show? |
How fast your object is travelling |
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What do curves represent on a distant-time graph? |
Acceleration or Deceleration |
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How do you find the speed? |
Vertical _________ Horizontal
500 ______ 30 |
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What can a change in velocity by a result of? |
A CHANGE IN SPEED A CHANGE IN DIRECTION |
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What is the unit for acceleration? |
M/s2 |
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What is the unit of velocity? |
M/s |
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What does a flat section show on a velocity-time graph? |
Steady speed |
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How do you calculate acceleration on a velocity-time graph? |
Vertical change ________________
Horizontal Change |
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What is the Force of Attraction between all masses? |
Gravitational Force |
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What is weight Measured in? |
Newtons |
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What is the resultant force? |
The overall force on a point or object |
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How is the resultant force found? |
By adding or subtracting the forces the forces that have an effect on the motion of an object |
By adding or subtracting the forces the forces that have an effect on the motion of an object |
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How does Resultant force affect velocity? |
It is a change in an objects velocity because it will change its state of rest or motion |
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If there is a resultant force what is there always? |
Acceleration |
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If there is no resultant force this means then the object will... |
Carry on moving at the same velocity |
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What are reaction forces? |
When two objects interact, the forces they exert on each other are equal and opposite |
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How does friction affect movement? |
- always acts in the opposite direction -to travel at steady speed they must balance the frictional forces |
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What is the most important factor to reducing drag? |
Keeping an object streamlined |
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What increases as the speed increases? And what does this mean for a car? |
Drag The engine has to work harder at faster speeds |
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Describe the process of objects falling through fluids to reach a terminal velocity. |
- when they set off the force of gravity is much more than the frictional force slowing them down - as speed increases so does friction - this reduces acceleration and the friction force will become equal to the accelerating force - this is terminal velocity |
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What causes things to fall at different rates? |
Air resistance |
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What is the terminal velocity of an object determined by? |
Drag in comparison to its weight |
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Explain the velocity example of the human skydiver. |
- without parachute open he has a small area - reaches terminal velocity of about 120mph - parachute open means more air resistance and is still the same force pulling him down - this means his terminal velocity comes right down to a safe speed |
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What is a stopping distance? |
The distance covered in the time between the first hazard and the complete stop |
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What is the reaction time? |
The reaction time is the one between the driver spotting a hazard and taking action |
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What affects your thinking distance? |
Tiredness Drugs/alcohol Bad Visibility Distractions Carelessness |
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What affects a braking distance? |
Speed
Quality of brakes
Quality of tyres
Road surface |
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What is the braking distance? |
The distance the car travels under the breaking force |
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What is the thinking distance? |
The distance the vehicle travels during the drivers reaction time |
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How is work done? |
When a force mores an object through a distance, energy is transferred and work is done. |
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When something falls what are the energy conversions? |
Potential energy = Kinetic |
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How do Space shuttles travel through the atmosphere? |
They have special materials which lose heat quickly allowing the shuttle to re-enter the atmosphere without burning up |
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Kinetic Energy Transferred = |
Work done by Brakes |
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What is an elastic object? |
An object that can go back to its original shape after being stretched or having force applied to it |
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What is the energy conversion of an elastic object? |
Elastic potential energy is then converted into kinetic energy |
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What is directly proportional to force? |
The extension of an elastic object |
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What is the equation for elascity? |
F = K X E |
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What does k stand for? |
Spring constant |
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What is Spring constant measured in |
N/m |
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What is the limit of proportionality? |
The maximum force that the elastic object can take and still extend proportionally |
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What happens if you increase a force past the limit of proportionality? |
The material will be permanently stretched |
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What is a powerful machine? |
One which transfers a lot of energy in a short space of time |
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