Physics: Post your doubts here!

[Minsa Fatima]

 

[anastasia grey113]

View attachment 62519

use Force = Change in momentum/time taken

this will give an answer of 0.5.
so select the answers which have a difference of 0.5
they r A and D
however as the ball hits the ground its momentum can never increase
it only decreases or stays the same (in elastic collisions) only
so there will be a decrease n answer will b D

hoping this helps

 

[Minsa Fatima]

use Force = Change in momentum/time taken

this will give an answer of 0.5.
so select the answers which have a difference of 0.5
they r A and D
however as the ball hits the ground its momentum can never increase
it only decreases or stays the same (in elastic collisions) only
so there will be a decrease n answer will b D

hoping this helps

Ans is C

 

[Roe Mir]

Guys how do you know the frequencies for open air and closed air columns?

 

[anastasia grey113]

Ans is C

oh well then
i think i need some help with this too :/
amina1300 any explanations for this?

 

[GarryTheGhost]

paper 11

question 5.
each box is 0.2A. x coordinates and y coordinates are only equal at one point and that is 0.8A
question 14
take moments about the end of the truck. (this will just be trial and error)
A) cannot because clockwise moment does'nt equal anitclockwise moment.
only viable option is B where a force 15kn*20m=300 anticlockwise and clockwise is 30*10m=300k so they are both equal.
question 32.
good luck.......

 

[Minsa Fatima]

use Force = Change in momentum/time taken

this will give an answer of 0.5.
so select the answers which have a difference of 0.5
they r A and D
however as the ball hits the ground its momentum can never increase
it only decreases or stays the same (in elastic collisions) only
so there will be a decrease n answer will b D

hoping this helps

P2 in opposite direction so they get added up 0.3+0.2=0.5

 

[anastasia grey113]

Ans is C

ohhhhhhhhhhhh i got it
its like the velocity is in the opposite direction now so that means it is 0.3- (-0.2)
that shows the momentum change in C is 0.5
n since momentum can only decreas answer is C

A and D r wrong cuz the difference is 0.65 - (-0.15)
this makes 0.70 not o.5

 

[Minsa Fatima]

 

[anastasia grey113]

is the answer C?

View attachment 62520

 

[amina1300]

View attachment 62519

You guys already go the answer but..oh well...
F= (p2- p1)/∆t
Since the ball is in opposite direction, it implies that
F= (p2+p1)/∆t

p2+p1 = 25* 0.02 = 0.5
Since the ball has the same mass the velocity before hitting the plate will be higher than the velocity after it bounces. So, therefore, p1 > p2, from the option C is the correct answer

 

[amina1300]

is the answer C?

yes it is C

 

[anastasia grey113]

View attachment 62520

well then thats easy
use I2R = Power to find the power for each current
but dont take current as -1
take it as 1 since power does not have a direction
ad the powers n youll get 500W
divide it by 2 n the answer will be 250 W

 

[GarryTheGhost]

question 5.
each box is 0.2A. x coordinates and y coordinates are only equal at one point and that is 0.8A
question 14
take moments about the end of the truck. (this will just be trial and error)
A) cannot because clockwise moment does'nt equal anitclockwise moment.
only viable option is B where a force 15kn*20m=300 anticlockwise and clockwise is 30*10m=300k so they are both equal.
question 32.
good luck.......

The question asks us about mean power. key word mean. power=i^2*R we only have one value for R so we leave it alone. for current we have 2 distinct values 2A and -1A. so we take the avg value of I^2. SO watch this yea, its so cool. (2^2)+(-1^2)/2=2.5A^2 times that by 100ohms becuase of I^2*R to get 250Watts

 

[GarryTheGhost]

well then thats easy
use I2R = Power to find the power for each current
but dont take current as -1
take it as 1 since power does not have a direction
ad the powers n youll get 500W
divide it by 2 n the answer will be 250 W

Bro that was not easy

 

[Shimmery woods]

que 43 please!!!!

 

[furuta]

15. mass=weight/gravity
600000/9.81=61162
KE=1/2 *61162*40*40
KE=12MV
Answer=C

29. W=QV
Fd=QV
F=1.6*10-19 *200/0.005
=6.4*10-15

thank you sooo much

 

[Shimmery woods]

que 2 please

 

[Shimmery woods]

que 30 anyone ?

 

[amina1300]

Bro that was not easy

I still dont get this one.. :/ why divide by 2 ?