Changes in speed
When an object is stationary it has an equal force pushing down and up. The downward force being gravity and the upward force being the surface the object is on. The object is not floating but it is not going into the ground.
When an object is accelerating it has the upwards and downwards forces but it also has forwards and backwards forces (drag and friction). The forward force is larger than the backward force when an object is accelerating.
When an object is going at a constant speed it has downward and upward forces as well as forward and backward forces. The forward and backward forces are equal, so the speed doesn't change even though the object is moving.
When an object is decelerating it has the equal upward and downward forces as well as forward and backward forces, but the backward force is larger than the forward one, slowing the object down.
Changes in shape
changes in shape affect momentum. Force= change in momentum/ time taken. An example of this is crumple zones in car decrease the force on the passengers.
Changes in direction
Which ever direction the force is greatest in will be the direction the object travels in.
what did you do for revision
ReplyDeleteI wrote out these blogs, and then I made posters on each point, and then I made flash cards! but I also did lots of past papers which was very helpful :)
DeleteTHANK YOU!!!
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Deletei still love you bae
DeleteNO PROBLEM Tiago!
Deletethis is so helpful!! More helpful than my teacher. :)
ReplyDeleteHaha thank you Jenna, good luck in the exam :)
DeleteThis is possibly the best thing I've ever discovered on the internet
ReplyDeleteI like to think so haha
DeleteJust kidding- thanks
Deletethis has wonderful answers
ReplyDeletethank you :)
Deletewhat are the forward and backward forces
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Deletethank u so much!!!this was very helpful.
DeleteForward force can be momentum and/or thrust
DeleteBackward is drag and/or friction
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ReplyDeleteThanks for your comment, I'm fairly sure they plagiarised me and am now getting in touch.
DeleteOMG thank you so much, these were so helpful, i got a mock exam coming up soon to go over the last term and this helped so much with my revision, thank you! :))
ReplyDeletedid you print off the past papers or can you buy them already printed?
ReplyDeleteI didn't print them, just looked at them online; if you can do this it saves time, money and the planet :) if not some schools will print them out and sell them as booklets but apart from that you mostly have to print yourself :P
DeleteSo well explained :) Thank you so much
ReplyDeleteis it thrust or friction as the forwards force??
ReplyDeleteThrust
DeleteExtremely helpful Hannah, thank you.
ReplyDeleteBy “forwards and backwards forces” and ‘drag and friction’ did you mean thrust and friction’ as drag is also a backwards force?
Thanks again :)
☺
ReplyDeleteThank you so much this really helps for my end of year exam
ReplyDeleteThanks gal
ReplyDeleteThanks so much for these notes, they're excellent!
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ReplyDeletewhat is resultant force
ReplyDeletehow to investigate friction??
ReplyDeleteHi... Just came across your blog and it's brilliant! Just a small thing I noticed when reading this particular post was that you stated drag and friction as forward and backward forces - surely, though the friction would be used to allow the car to push off the road, both these forces would be counted as opposing forces and therefore backward?
ReplyDeleteTysmmm
ReplyDelete