Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
FORCES
| Question | Answer |
|---|---|
| can you see a force? | no you can not. stupid but you can often see what it does! |
| example of a non-contact force | magnets, gravity |
| example of a contact force | anything where you have to to touch something, for example pushing someone over or hitting a hammer through a wall |
| who is newton meter named after | Isaac Newton |
| when reading a newton meter you must: | check the zero reading, take readings at eye level |
| a parachuter is pulled down to the ground because of their ... | weight |
| a parachuter is pulled upwards when parachute is inflated because of.... | air resistance underneath parachute |
| arrows on diagrams are used to.. | represent direction and size of forces |
| who discovered gravity? | Brahmagupta-II, over 1,000 years before newton. stop saying it was newton you nasty lump of unripe gelatine |
| what pulls an object down to the ground? | WEIGHT. NOT GRAVITY!!!!!!!!!!!!!!!!!!!!! |
| what is a contact force | contact has to be made, like hooking a newton meter to an object (two things have to touch) |
| what is non-contact force | where contact does not have to be made, eg magnets, gravity |
| friction will always speed things up, true or false? | FALSE. it will always try and slow things down. |
| when friction is caused by something moving through the air, what is is called | air resistance/drag |
| why are your hands never perfectly smooth | there are rough surfaces, bumps, holes etc on ever part of your skin. you are uneven and greasy. ew |
| what will cause a sailing boat to move forward if it is on the water | thrust |
| jet, which direction will it move? | the object will not move because there is no resultant force |
| What can happen when a force is exerted on an object? | It can change the objects speed, direction of movement or shape |
| Another name for a Newton meter | Force meter |
| Force is measured in | newtons |
| What is a force arrow | Arrows on diagrams representing direction and sizes of forces |
| Simplified force arrow | A simplified force arrow diagram shows us the resultant forces on the object |
| Forwards and backwards forces are | horizontal forces |
| Friction opposes... | motion |
| How is friction created? | Whenever two touching objects or surfaces move past each other. |
| Newtons Third Law | Newton’s third law says that for every action there is an equal and opposite reaction. This means that when one object pushes on another with a force, the other object pushes back on the first object with the same force. |
| How does Newton's Third Law apply to us? | We cannot move independently? We require a force acting upon us from elsewhere. When we want to move, our feet try to push the ground backwards. But it is the friction from the ground that pushes us forwards. |
| What is pressure | Pressure is a measure of how much force is acting upon an area. |
| How can we find out how much pressure is being used? | Pressure can be found using the equation pressure = force / area. Therefore, a force acting over a smaller area will create more pressure. |
| Measuring pressure | Mass measures of how much matter there is; force is the pull of the Earth's gravity on that mass. Each kg of mass is pulled down by Earth with a force of 10 N. Convert this to force (N) multiply mass by 10. Pressure = force ÷ area. |
| Who uses knowledge of forces and pressure? | When structural engineers and architects design and construct a building, they need to make sure the foundation is strong enough and that the building doesn't sink into the ground. |
| Tell me about stiletto's! | A person wearing a stiletto exerts more pressure on the ground than an army tank! The army tank uses caterpillar tracks to spread its weight (and therefore force) over a larger area, in order to reduce the pressure. If it didn't, it would sink! |
| How does a newton meter work? | Force meters contain a spring connected to a metal hook. The spring stretches when a force is applied to the hook. The bigger the force applied, the longer the spring stretches and the bigger the reading. |
| How does something float? | Objects float in water when their weight is balanced by the upthrust from the water. The object will sink until the weight of the water it pushes out of the way is the same as the weight of the object. |
| What is reaction force? | When an object rests on a surface such as the ground, reaction force from the ground balances its weight. The ground pushes up against the object. Reaction force is what you feel in your feet as you stand still. Without it you would sink into the ground. |
| How can friction be useful? | friction between our shoes and the floor stop us from slipping friction between tyres and the road stop cars from skidding friction between the brakes and wheel help bikes and cars to slow down |
| Why can we slide on ice but not concrete? | Frictional forces are much smaller on smooth surfaces than on rough surfaces, which is why we slide on ice but not on concrete. |
| Streamlining and air resistance | Cyclists crouch down low to reduce air resistance helping to cycle faster. Streamlined helmets have special, smooth shapes allowing air to flow over them easily. Also vehicles - Smooth shapes make air resistance smaller -allows them to travel furthe |
| What is a moment? | A moment is a turning effect of a force. Forces can make objects turn if there is a pivot. |
| How to calculate a moment | the distance from the pivot that the force is applied the size of the force applied moment = force × distance |
| Deformation | Elastic materials, and objects such as springs, change shape when a force is exerted on them: stretching happens when the material or object is pulled compression happens when the material or object is squashed |
| Hookes Law | Hooke’s Law says that the extension of an elastic object is directly proportional to the force applied to it. if the force applied is doubled, the extension doubles if no force is applied, there is no extension |
| What happens to the air resistance on a car as the car goes faster? | It increases |
| A force of 4 N acts on a lever 2 m from the pivot. What is the moment? | The moment is 8 Nm. Remember: moment = force x distance from pivot. |
| Gravity is an example of what? | A Non-Contact force |
| What sort of energy does friction always produce? | Heat |
Created by:
Frankiek
Popular Physics sets