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64 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is the difference between speed and velocity? |
-speed is how fast without direction -velocity is how Fast with direction |
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Speed = ? |
Distance ÷ time |
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What does the gradient of a distance-time graph show? |
How fast the object is traveling |
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The steeper the distance time graph the... |
Faster the object is going |
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What do downhill sections represent on distance time graphs? |
The object is going back to its starting point |
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steepening curve on a distance time graph |
The object is accelerating (speeding up) |
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What does a leveling off curve show on a distance time graph? |
The object is decelerating (slowing down) |
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used to measure the Gradient |
The scales of the axis |
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What is the formula for speed and gradient? |
Change in distance ÷ time taken |
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= force = |
Mass x acceleration |
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What is acceleration? |
How quickly the velocity is changing |
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What is the formula for acceleration? |
change in velocity ÷ time taken |
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units of acceleration |
M/s² |
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What is Newton's 1st law? |
If the forces acting on an object are balanced then the object will remain moving as it was before |
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What is Newtons 2nd law? |
If the forces acting on an object are unbalanced then the object will accelerate in the direction of the resultant force |
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What is the resultant force? |
The overall force of an object (which is stronger and my how much) |
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What is vehicle braking distance affected by? |
- speed -weather conditions -condition of driver Condition of road -mass of vehicle |
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What is overall stopping distance? |
=thinking distance + vehicle braking distance |
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What is thinking distance? |
The drivers reaction time and condition of the driver. |
👨👩 |
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What affects thinking distance? |
-drugs/alcohol influence - age -speed -tiredness -distractions (billboards, shops, passengers, that cute puppy etc) -eyesight |
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What affects vehicle braking distance? |
-good/bad tires -good/bad weather conditions - mass of vehicle -good/brakes - good/ bad road conditions |
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What is Hooke's law? |
Extension is directly proportional to the force stretching the spring (ask if we need to learn it) |
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Weight =? |
Mass X force of gravity (gravitational field strength) |
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What is the force of gravity? |
10 n/kg |
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What is weight measured in? |
Newton's |
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What will happen if the resultant force on a stationary object is zero? |
The object will remain stationary |
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What must the resultant force be to keep an object moving at a steady speed? |
Zero resultant force |
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What will a non-zero force produce? |
Acceleration (or deceleration ) |
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What five forms can acceleration take? |
-starting -stopping -speeding up -slowing down -changing direction |
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F=ma. Or?? |
A=F/m |
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Reaction forces are:? |
Equal and opposite |
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What direction does friction act? |
The opposite direction to movement |
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When does drag increase? |
As speed increases |
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Why does an object reach terminal velocity? |
-As speed increases the friction builds up -acceleration reduces -frictional force is equal to the accelerating force -object won't accelerate any more |
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Work done=? |
Force x distance |
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What is gravitational potential energy? |
Energy due to height |
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Gravitational potential energy=? |
Mass x g x height |
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What is gpe measured in? |
Joules |
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What is kinetic energy? |
Energy of movement |
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Kinetic energy =? |
½ x mass x speed² |
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Energy can never be........ |
Created or destroyed - only converted into different forms |
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Kinetic energy gained = |
Potential energy lost |
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The extension of a stretched spring is directly proportional to what? |
The load or force |
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What is the equation for extension? |
F=k x e Ask what is k. Constant? |
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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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Power = ? |
Work done (or energy transferred) ÷ time taken |
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What is power measured in? |
Watts (or j/s) Ask about calculating power |
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Momentum =? |
Mass x velocity |
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What is momentum |
Property of moving objects |
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What makes an object have more momentum? |
The greater the mass and velocity |
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Why is momentum a vector quantity? |
It has size and direction |
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Momentum is a vector quantity, what is another? |
Velocity |
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What is a closed system? |
No external forces act |
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What is conservation of momentum? |
The total momentum before an event is the same as after the event |
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What causes a change in momentum? |
When a force acts on it |
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What causes a faster change in momentum? |
A larger force |
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What are regenerative brakes? |
Brakes that make use of the heat energy and use the system that drives the vehicle to do the majority of the braking |
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How do regenerative brakes work? |
-They put the motor into reverse so the wheels are slowed -motor acts as an electric generator converting energy into electrical energy Energy converted to chemical energy in the vehicles battery |
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What are safety features on a car? |
-crumple zones -side impact bars -seat belts -air bags |
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How do crumple zones work? |
The front and back of the car crumple up on impact |
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What are side impact bars and what do they do? |
Strong metal tubes fitted into car door panels. Direct kinetic energy to other areas of the car |
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How do seat belts reduce force? |
They increase the Time it takes to stop and some energy is absorbed by the belt. |
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How do air bags work? |
Slow you down gradually, preventing people hitting hard surfaces |
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When do cars reach their top speeds? |
When the resistive force equals the driving force |
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