1456098
Descrição
FlashCards por beth.tripp, atualizado more than 1 year ago
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Criado por beth.tripp
aproximadamente 10 anos atrás
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| Questão | Responda |
| What is Gravitational Force? | it is the force of attraction between all masses |
| What is mass? | The amount of 'stuff' in an object which will have the same value anywhere in the universe. |
| What is weight? | Caused by pull of gravitational force. In most questions the weight is the force of gravity pulling it towards the earths core. |
| What happens to an object on the earth or on the moon? | It has the same mass no matter on the earth or moon but weight will be different because the gravitational force will pull on it less. |
| What is resultant force? | The overall force on a point or object |
| How do you work out resultant force? |
If the forces are parallel to each other in the same or opposite direction you work it our by adding or subtracting e.g. 10n-10n=0n so the resultant force is 0
Image:
forces-plane (image/jpg)
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| What does resultant force mean? | A change in velocity. If there is a resultant force acting on an object it will change its state of rest or motion. |
| What will happen if the resultant force on a stationary object is 0? | The object will stay stationary as there has to be a resultant force to get them started. |
| What does no resultant force mean? | no change in velocity and it will just continue at the same velocity as a resultant force means acceleration. |
| What does a non-zero resultant force produce? | Produces acceleration F=ma |
| What needs to happen to travel at a steady speed? | driving force needs to be balanced with the frictional forces. |
| what does drag do as speed increases? | it increases |
| What does the terminal velocity depend on? | shape and area |
| What is terminal velocity of an object determined by? | drag in comparison to weight |
| what is stopping distance? | the distance covered in the time between the driver spotting a hazard and the vehicle coming to a complete stop |
| how do you work out stopping distance? | thinking distance + braking distance |
| what is thinking distance? | the distance the vehicle travels during the driver's reaction time. |
| what is braking distance? | the distance the car travels under the braking force. |
| what is kinetic energy transferred? | work done |
| what is the extension of a stretched spring? | directly proportional to the load or force applied. F=ke |
| what is power? | the rate of doing work i.e. how much per second. p=e/t |
| what is power measured in? | watts or j/s |
| what do you know about momentum? | =mass x velocity momentum is a property of moving objects. The greater the mass of an object and the greater the velocity the more momentum the object has. |
| momentum before=? | momentum after In a closed system the total momentum before an event e.g. collision is the same as after the event this is called conservation of momentum. |
| why do forces cause changes in momentum? | when a force acts on an object , it causes change in momentum. larger force=faster change of momentum |
| explain regenerative brakes | they use the system that drives the vehicle to do the majority of the braking rather than converting the kinetic energy of the vehicle into heat energy, the brakes put the motor in reverse with the motor running backwards and the wheels are slowed but at the same time the motor acts as a generator converting kinetic energy into electrical energy that is stored as chemical in the vehicle's battery. |
| what are cars designed to do? | convert kinetic energy safely in a crash |
| what charges are attracted and repelled? | |
| what is current? | (A) the flow of electric charge round the circuit. current will only flow through a component if there is a potential difference across that component . I=Q/T Current=charge/time |
| What is potential difference? | the driving force that pushes the current round. |
| what is resistance? | is anything in the circuit which slows flow down measure in ohms. |
| what will the current be the greater the resistance across a component? | the smaller the current that flows |
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