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Descrição
FlashCards por Lauren Robinson, atualizado more than 1 year ago
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Criado por Lauren Robinson
mais de 10 anos atrás
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| Questão | Responda |
| On a distance-time graph, what does the gradient show? Therefore what do flat sections show? | The speed It's stationary |
| On a distance-time graph, what do curves represent? Therefore what does a steepening curve show? And what will a leveling off curve show? | Acceleration/deceleration Speeding up Slowing down |
| What is the difference between speed and velocity? | Speed is the rate at which something is travelling (how FAST) whereas velocity also takes the DIRECTION into account |
| How do you calculate speed from a distance-time graph? | Speed = distance / time |
| If a pea traveled at 14 m/s in 0.4 seconds, what is its acceleration? | Acceleration = change in velocity / time A = 14 / 0.4 A = 35 |
| How do you find speed, distance and acceleration from a velocity-time graph? | Speed = the Y axis Distance = area under the graph Acceleration = gradient (vertical change / horizontal change) |
| Explain the difference between mass and weight. What units are they measured in? | MASS- Always the same as it is the amount of matter inside an object (Kg) WEIGHT- Caused by the pull of the gravitational force (N) |
| If an object has a resultant of zero, can it be moving? Can it be accelerating? | The object can be moving but not accelerating or decelerating because the resultant force is the total force acting upon an object, and if there is no force on it, it cannot accelerate or decelerate. |
| Define terminal velocity | Terminal velocity is the maximum speed an object can fall at and is determined by its drag in comparison to its weight |
| What are the two different parts of the overall stopping distance of a car? | Thinking distance and Breaking distance |
| The formula for work done is force x distance. If a branch is dragged 12m with a pulling force of 535 N, how much work is done? | WD = F X D WD = 535 X 12 WD = 6420 J |
| A 4 kg object is taken 30m up a hill. If g = 10 N/km, how much gravitational potential energy is does it have at the top of the hill? (GPE = mass x g x height) | GPE = mass x g x height GPE = 4 x 10 x 30 GPE = 1200 J |
| What is the equation that relates the force on a spring to its extension? | F = k x e (k = spring constant) (e = extension) |
| What happens to an elastic object when it is stretched beyond its limit of proportionality? | It will stay permanently stretched at this length |
| The formula for momentum is mass x velocity. If the total momentum of a system before a collision is zero, what is the total momentum afterwards? | Zero. Because 0 X any number always = 0 |
| What is the advantage of using regenerative breaking systems? | They store the energy of breaking rather than wasting it |
| How are: a) Seat belts b) Crumple zones c) Air bags useful in a car crash? | a) They stretch slightly, increasing the time taken for the wearer to stop and some kinetic energy is absorbed by the seat belt stretching. b) Kinetic energy is converted into other types of energy as it changes the cars shape. Also increase impact time, decreasing the forces produced by the change in momentum. c) Slow you down gently to prevent you from hitting the hard surfaces in the car |
| How does adding a roof box change the top speed of a car? | It reduces the top speed as the car becomes less aerodynamic, increasing air resistance as well as becoming heavier. |
| What causes the build up of static electricity? When the static builds up, which particles move? | A build up of static is caused by friction. When two objects are rubbed together, electrons get scraped off one, and onto another, causing one of the objects to be positively charged and the other to be negatively charged. POSITIVE CHARGES NEVER MOVE. |
| Fill in the blank. The ________ the resistance across a component, the smaller the current that flows. | Greater |
| How does the resistance of a component change with its temperature (in terms of ions and electrons)? | 1) Some electrical energy is converted to heat energy 2) The heat causes the ions to vibrate more 3) Difficult for electrons to get through the resistor 4) The current can't flow as easily and the resistance is increased |
| Give 2 applications of LED's | 1) Lighting- use small amount of current 2) Indicate the presence of current in a circuit 3) Used in traffic lights and remote controls |
| How does the resistance of an LDR change with the intensity of light? | Bright light = falling resistance Dim light = high resistance |
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