Karteikarten
P3
Karten in diesem Stapel (57)
- 1Increasing the speed reduces......the time needed to cover the same distance
- 2On a distance time graph, what does a steeper gradient mean?A higher speed
- 3What does a straight line on a distance-time graph indicate?That the speed is constant
- 4What does a curved line on a distance-time graph indicate?That the speed is changing
- 5What is a change of speed per unit of time called?Acceleration
- 6The area under a speed-time graph is equal to what?The distance travelled
- 7Is velocity a vector or a scalar?Vector (both size and direction)
- 8How do you work out the relative velocity for two cars that are moving in the same direction?Find the difference
- 9How do you work out the relative velocity for two cars that are moving in different directions?The sum of the individual velocities
- 10Why is a vehicle going round a roundabout accelerating?It has to apply force towards the centre of the circle to keep changing direction
- 11If the forces are balanced at what state is the vehicle?Constant speed or rest
- 12What are the 4 things that increase reaction time for a driver?If they are... tired, under the influence of alcohol/drugs, travelling faster or distracted
- 13What are the 3 things that increase braking distance?-Poor road conditions
-Worn brakes
-Speed is increased - 14What are the 3 things that ensure safe driving?-Keeping distance between you and other vehicles
-Different speed limits
-Slow down in poor conditions - 15What are the 5 factors that affect braking distance?-Bigger mass=increased BD
-Higher speed=increased BD
-Worn breaks=increased BD
-Worn tyres=increased BD
-Increased breaking force=reduced stopping distance - 16What increases linearly with speed?Thinking distance
- 17What increases as a squared relationship?Braking distance
- 18When is work done?When a force moves an object in the direction in which the force acts
- 19What is weight a measurement of?The gravitational attraction on a body acting towards the centre of the Earth
- 20What is power?The rate at which work is done
- 21A persons power is greater when they run than when they walk. True or false?True
- 22What does the power rating of a car depend on?Its engine size
- 23How does the braking distance of a car increase?With increasing speed (but not proportionally)
- 24What happens to a car's K.E when it stops?It changes into heat in the brakes, tyres and road.
- 25Work done by brakes=Loss in K.E
- 26Braking force x braking distance =Loss in K.E
- 27What happens to the K.E and the braking distance when the speed of the car doubles?They quadruple
- 28What are the 5 factors that affect the fuel consumption of a car?-amount of energy needed to increase its K.E
-Amount of energy needed to do work against friction
-speed
-how it's driven
-road conditions(rough) - 29What are 4 issues with electric cars (solar powered and battery driven)?-Battery is large
-Limited range before they need recharging
-Expensive to buy
-Rely on sun - 30What are two advantages of electric cars?-They don't (directly) pollute
-Cost of recharging is low - 31How do battery powered cars indirectly pollute?Recharging the batteries requires electricity from power stations which pollute
- 32Although biofuels may reduce carbon emissions, why is this not certain?Because deforestation leads to an increase in CO2 levels
- 33What spreading momentum change over a long time do?Reduces the force
- 34How can we reduce acceleration (and therefore force)?-Increasing stopping/collision time
-Increasing stopping/collision distance - 35What are the 5 features that reduce acceleration?-Crumple zones
-Seat belts
-Air bags
-Crash barriers
-Escape lanes - 36What do modern cars have that help absorb energy in a crash (4 things)?-Brakes that get hot
-Crumple zones that change shape
-Seat belts that stretch
-Air bags that inflate and squash - 37Why does seat belts stretching help absorb energy?Converts K.E into elastic energy
- 38What are the 3 reasons why drivers don't like wearing seatbelts?-Risk of chest injury
-Could be trapped in fire
-Could encourage driver to drive more carelessly as he/she knows they're protected by seatbelt - 39What is the best way to gain safety information?By using crash tests with real vehicles and dummies
- 40What are ABS brakes?A primary safety feature which helps to prevent a crash
- 41How does the ABS system work?Wheel-speed sensors send information to a computer about the rotational speed of the wheels. The computer controls the pressure to the brakes to prevent the wheels locking up. This increases the braking force just before the wheels start to skid
- 42What are two other primary safety features?-Cruise control (stops a driver becoming tired and pressing harder on the accelerator)
-Electric windows and paddle shift controls (allows driver to concentrate on road) - 43What are the two things that affect the size of air resistance?Cross sectional area and speed
- 44When does air resistance only have effect?When it is large compared to the weight
- 45What is the journey of a parachutist like in terms of forces?1)Accelerates, displacing more air molecules a second. Air resistance increases, reducing his acceleration
2)Weight and air resistance are equal = terminal speed
3)Parachute opens and air resistance increases due to large surface area. Parachutist decelerates and air resistance decreases
4)New lower terminal speed - 46What are three qualities of the gravitational field strength?-Unaffected by atmospheric conditions
-Varies with position on the Earth's surface
-Varies with height above/below Earth's surface - 47What does an object held above the ground have?Gravitational potential energy
- 48What are the 4 steps of a bouncing ball?1)Ball has GPE but no K.E
2)Reached ground-has K.E but not GPE
3)Ball squashes-has EPE-converted to K.E as it leaves ground
4)At top of bounce has GPE - 49What is the loss in GPE in a skydiver due to?The work against friction (air resistance)
- 50change in GPE =work done against friciton
- 51What do the riders at the top of a roller coaster ride have?GPE
- 52What happens when the roller coaster is released?Converts GPE into KE as it falls
- 53Loss in GPE=Gain in KE
- 54Why does each peak in a roller coaster have to be lower than the one before?Because some energy is transferred to heat and sound due to friction and air resistance
- 55GPE at top of roller coaster=KE at bottom + energy transferred due to friction
- 56If speed doubles what happens to KE?It quadruples
- 57If mass doubles, what happens to KE?It doubles too
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- GCSE Physics (P3) Karteikarten am P3, erstellt von Anna Hollywood am 02/12/2013.
- Erstellt von
- Anna Hollywood
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