Physics 9702/21

[sma786]

What did you guys get for the force of that ball thrown in free fall ?

just used the simple formula f=ma, i thiiinkkk it was something like 1.5N
what was ur answeR?

 

[sma786]

Ohhh.. I remember.. I got theta as 44.2.. Cant remember my T value... What did you get?
I hope its low! At most it should be 43 for an A..

i got 45.8

 

[jose machado]

what ball falling freely? there was nothing like that

 

[1357913579]

for finding the energy lost
ke=pe+enery lost
wasnt kintetic enery 5. something
and potential energy 4. something
?

 

[Jisu]

cuz it asked what was the frictional force and you knew that KE=GPE + HEAT FRICTION cuz it was upwards and when it reached 21m V=0 by calculating HEAT enrygy u divided by 21m and got the force by W=FD

Did the same..

 

[Jisu]

44.2 WOOOOOOOWOO

Got the same!!!

 

[Jisu]

T is 49.5

YESSSSS

 

[Jisu]

The first page..base units stuff was easy
Then the last page alpha scattering was good
I got 8:1 and 1:8 for the ratio stuff
Energy conventions I did from chemical to electrical for battery
And for resistor I did electrical to chemical and heat
Wat about the question after that..the rate of energy transfer for battery and resistor A??
The vector question I got 49.5 for tension and 44.2 degrees
For the other question with the falling ball..I got KE and then PE..minus the two to get the energy lost or whatever
For force I did work done is equal to force times distance so just divide remaining energy by height which is 21m...can't remember answer though
For the kinetic model..u just say they collide with the Walls, change in momentum, force exerted thus pressure
For ideal gases, always elastic collisions because relative speed of approach is equal to separation and there are no intermolecular forces
For O to P thingy idk what I did..just wrote its a minima, pi radians phase difference and lambda by two path difference..not sure if its right though

 

[Omar99]

ke was just o.5*mass*initial speed squared

The ratio was just 8 and 1/8 the force was 16/21

How did u get 1/8,
I got it 2/1.

 

[Jisu]

How did u get 1/8,
I got it 2/1.

Are u sure u got the cross sectional area right?? It was pi times (d/2)^2 and the one is the same but with 2d

 

[jose machado]

i said for elastic collisions because KE is conseverd as the speed of approach = the speed of seperation as no heat is evlolved in the collision and there are no intermolecular forces! For OP u said that at P there was a point of maxima as the path differnce was 6 lambda indicating pointo of constructive interference ! and halfway betwee o p there was a point of minama The conditions were coherence same single frequency (monochromatic) maintain the same phase relationship and incident waves had to be perfectly in phase (2pi) for cpmstructive interference to take place

 

[WILSON ODHIAMBO]

And what 2 changes were to be made to the experiment for OP???