## Saturday, 31 March 2012

### Movement and position

1.1 Units: kg, m, m/s, m/s2, N, s, N/kg

a) Movement and position
1.2 understand and use distance-time graphs

Distance -time graphs

The gradient of a distance-time graph=speed
s=d/t
Distance isn't increasing-gradient=0, hence speed=0---->object is stationary (not moving)

The steeper the graph, the greater the speed as the gradient is steeper.
If the graph is curved, then the speed must be changing. If it is curving upwards (blue line), the speed is increasing, if it is curving downwards, the speed is decreasing. So the gradient of the graph also tells us how the speed is changing.

Instantaneous speed=How fast an object is moving at a particular instant.
The gradient of the tangent at a point on the distance-time graph gives us the instantaneous speed.

1.3 recall and use the relationship between average speed, distance moved and time:

average speed=distance moved/time taken
s=d/t

1.4 recall and use the relationship between acceleration, velocity and time:

acceleration=change in velocity/time taken
a=(v-u)/t
where v=final velocity
u=initial velocity
t=time

1.5 interpret velocity-time graphs

1.6 determine acceleration from the gradient of a velocity-time graph

the gradient at a point on the velocity-time graph gives you the acceleration

1.7 determine the distance travelled from the area between a velocity-time graph and the time axis

basically, the area under a velocity time graph = distance travelled

1. Terrible notes!

1. nooooooooo they are awesome and amazing
- an ex-student from BSS

2. Agree, this is helpless!!

3. It is funny because the same person wrote both of those comments as they are only written 13 mins apart :P

I don't know why that person thought that though as I find the notes very accurate and useful.

4. Agree, this is very accurate and useful.

I am a very important physics person so I know what I am talking about and I am totally not the guy who wrote the amazing comment before me.

5. Thank you so much, this really helped me with revising for my Science test tomorrow. :)

6. Thanks mitchelle this is so helpful =]

7. very helpful. saved alot of time for revising

8. this helped me alot, thankyou! ;D

and I think that you are a very nice person
love u <3

10. oh you are so helpful love ya kisses :* ♥

11. very helpful, but sometimes you could add a bit more detail...but overall, its very good! :)

12. No doubt a very helpful notes! Thanks!
Loved it! :D

13. terrable :(

14. Thank you so much! You helped me revising before my test.

Please tick a box showing your reaction, and any feedback is appreciated. :)

Note: This blog will no longer be updated as I finished IGCSEs in 2012. Sorry! :( If you are interested in buying IB notes though, please contact me. :)