Edexcel PHYSICS Doubts

[ashish]

through out  the whole free fall the Acceleration is 9.81

what changes is the SPEED

speed decreases going down due to air resistance due to the formula :

Air resistance is directly proportional to Square Speed  *meaning speed to the power of two *

I'm sorry but if u are doing AS physics Edexcel Unit One , You don't need to know that cuz the air resistance is ALWAYS there . Unless it is stated in the Q that it is negligible .

I'm sorry but I don't know it or perhaps I'm too sleepy to focus -.-

gg i think you got something wrong

when falling the speed of the object increases, that is the body accelerate until it reaches terminal velocity.check the graph

and while throwing the object upward, the object suffers a deceleration and after some time it's velocity will become 0

on the other hand if there is no air resistance the object will fall with constant acceleration  (g) !

[The Golden Girl =D]

gg i think you got something wrong

when falling the speed of the object increases, that is the body accelerate until it reaches terminal velocity.check the graph

and while throwing the object upward, the object suffers a deceleration and after some time it's velocity will become 0

on the other hand if there is no air resistance the object will fall with constant acceleration  (g) !

My Bad 

Thanks for clearing this out for us

[blackberry]

well actually according to the graph shouldnt the object be decelerating??
see thats the part where i get confused when the object falls it accelerates and decelerates and the speed/velocity
increases and decreases at the same time so i dont get it!! what is going on?? (ahhhhhhhhhhhhhh!!!!)

[astarmathsandphysics]

the acceleration is the slope and the slope is decreasing.
The speed is increasing but the rate at which it is decreasing - the acceleration - is slowing.

[The Golden Girl =D]

I don't get what Q 17] b)iii) means  

And Q 16]b)ii) ...I just go blank when I read the Q , what does the Q want ? -.-


as well as Q19] b)ii) ... how do I Answer it +i don't get how will the drawing will look like ?  

Thanks In Advance

[elemis]

QUestion 17
Basically they're asking if I create one small bubble and another large bubble and let them go, explain why the big bubble catches up with the smaller one ?

Question 16
How suitable are the Diesel Generators for use in this project ? Remember, standby means if the other power sources fail Diesel generators will be switched on.

So in effect they must provide the same power output or even more than the power output of the other power sources.

Question 19

In such a case where you are unsure draw a small diagram at the bottom of the page and on the lines explain your working fully. This avoids misunderstandings.

[elemis]

Question 19

Using tan :

tan x = 4.8/0.485

x = 84.2 degrees.

[The Golden Girl =D]

QUestion 17
Basically they're asking if I create one small bubble and another large bubble and let them go, explain why the big bubble catches up with the smaller one ?

Q17] catches up means that it'll be at the same level after a while *that's what i understood*

Answer says :       if r increases ,speed increases too

1. I don't get why increases ?  2.if it does increases why does it catch up in the end ?


Thanks mate

[elemis]

Q17] catches up means that it'll be at the same level after a while *that's what i understood*

Answer says :       if r increases ,speed increases too

1. I don't get why increases ?  2.if it does increases why does it catch up in the end ?


Thanks mate

If you look at the equation you'll notice radius is on the numerator. If the numerator of a fraction increases in size then the fraction becomes LARGER in value.

Therefore, as radius increases the value of the fraction, in this case speed, will increase too.

The smaller bubble has a lower speed compared to the larger bubble.

[The Golden Girl =D]

If you look at the equation you'll notice radius is on the numerator. If the numerator of a fraction increases in size then the fraction becomes LARGER in value.

Therefore, as radius increases the value of the fraction, in this case speed, will increase too.

The smaller bubble has a lower speed compared to the larger bubble.

Aha Okay , Now I get it ..Thanks mate

[zbzbzb25]

These questions are from A2 edexcel phy book pg. 89 (qn 2 & 3)
Lawrence's second cyclotron, built with the assistance of Stanley Livingstone,was 25 cm in diameter.(continued?
it accelerated protons to 1 MeV.
(a) calculate the speed of these protons.
(b)calculate the momentum of these protons.
(c)Calculate the magnetic field strength Lawrence used in this cyclotron, assuming that the protons move in a circle around the very edge of the machine.
(d)Calculate the frequency of the voltage that Lawrence and Stanley had to apply to achieve this proton acceleration.

and another question

The Large Hadron Collider is a giant circular accelerator near Geneva in Switzerland.?
The LHC website povides some facts about it :
1- the circular ring has a circumference of 27km
2-each proton goes around over 11000 times a second
3-each proton has 7 tera eV of Kinetic energy ( tera is ten to the power of 12)

(a) calculate the speed of these protons.
(b)calculate 1/2 m (v squared) for these protons using mass of proton equal to 1.67* ten to the power of (-27) kg.
(c) how does your answer to (b) compare with the 7 T(tera) eV of kinetic energy the
protons are given through the p.d. acceleration?
(d) Explain this difference.

[astarmathsandphysics]

1a)1MeV=1/2mv^2
10^6*1.6*10^-19=1/2*1.67*10^-27v^2 so v=1.38*10^7m/s
b)p=mv=1.67*10^-27*1.38*10^7=2.3*10^-20 kgm/s
c)B=mv/er=1.67*10^-27*1.38*10^7/1.6*10^-19*0.125=1.152T
d)f=v/2%pir=1.38*10^7/6.28*0.125=17.6MHz
2a)v=2pi r f=27000*11000=2.97*10^8m/s
b)1/2mv^2=1/2*1.67*10^-27*(2.97*10^8)^2=7.4*10^-11J
c)7TeV=7*10^12*1.6*10^-19=1.12810^-6J
d)Much of this energy is given off as electromagnetic radiation through the sides of the accelerator as the protons accelerate in a circle

[astarmathsandphysics]

I also ignored relativity - bad idea since the protons have reached may 99% of speed of light.

[meeeeeee]

For A2 physics, do we need to know the details of milikan's oil drop experiment?

[MKh]

u wil hav 2 chek in d specification...