Physics P2 Help Required

[MAVtKnmJ]

May/June 2007

I'm confused about question 3 part c (ii). How do you calculate the ratio?

I'm also confused about question 4 part c and d. Why is the horizontal velocity 18, shouldn't it be 0???
For same question, how do you draw the vector diagram and how do you find the angle? I did tan theta vertical velocity / horizontal velocity but getting an answer larger than 50 degrees.

Thanks in advance!

 

[intel1993]

in q3 c) i)

p1 v1 = p2 v2
v1/v2 = p2 /p1

1/(1/1600) so ans = 1600

 

[intel1993]

no horizontal velocity should be 18 as shown in diagram ......the object is not falling vertically bt following a projectile motion so theere must be some given velocity.......which is 18...

so in vector diagram horizontal vector is 18
n vertical vector is 25........

n remember the angle which should be taken must be between resultant and horizontal vector n u will find ur ans to be 44.09 degree....

 

[MAVtKnmJ]

in q3 c) i)

p1 v1 = p2 v2
v1/v2 = p2 /p1

1/(1/1600) so ans = 1600

I'm not sure why you calculated the answer for part (i) when I already mentioned in my post that I need to know how to do part (ii) not (i)

 

[MAVtKnmJ]

no horizontal velocity should be 18 as shown in diagram ......the object is not falling vertically bt following a projectile motion so theere must be some given velocity.......which is 18...

so in vector diagram horizontal vector is 18
n vertical vector is 25........

n remember the angle which should be taken must be between resultant and horizontal vector n u will find ur ans to be 44.09 degree....

Can you draw this in mspaint and upload a pic to show me?
Thanks!

 

[intel1993]

q3 c ii) as we know mean sepeartion ( V )1/3
i mean cuve root of volume...

so first calculate it for water vapours and then in liquid
divide them u will get ans 2 be 11.7............

 

[princesszahra]

i heard ppl didnt do this one well
so thresholds will be low this time for p3's

 

[intel1993]

ok this is the picture for q4 d)

 

[MAVtKnmJ]

q3 c ii) as we know mean sepeartion ( V )1/3
i mean cuve root of volume...

so first calculate it for water vapours and then in liquid
divide them u will get ans 2 be 11.7............

I have no idea what your talking about dude, when did we learn this in our syllabus?

Plus I don't see any image of the vector diagram!

princesszahra this is regarding a past paper not the current paper

Edit

Now I see the image! Thanks for the explanation!

 

[MAVtKnmJ]

Another question bugging me is Q4 from May/June 2004. Need explanations of part b (i) and part c.

Thanks in advance!

 

[intel1993]

bt our teacher told us that when u wre given wvolume and th question is baout the mean seperation just take cube root of the volume u will get the ans.....
..

 

[princesszahra]

opppppppssssss soryy!

 

[intel1993]

btq zahra u r talking abt current p3 papers happend....(mj 2010)
u r saying that grade threshold wud be low this tyme ???

 

[MAVtKnmJ]

bt our teacher told us that when u wre given wvolume and th question is baout the mean seperation just take cube root of the volume u will get the ans.....
..

Strange our teacher has never told us this! Oh well thanks I'll try it this way, check the difficulty I'm having with my other question.

Thanks!

 

[intel1993]

q4 b i) F= mv- mu / t (derived the formula using rate of change of momentum)

put the values in the formula u will get the ans...

F= m(v-u)/t
F= 35/1000(-4.5 -(3.5))/0.14 (when ball going upward took that direction velocity in negative)

F= -2

so magnitude = 2 n negative side shows the direction which we supposed earlier

so upwards......

 

[intel1993]

Q4 c:

linear law of mommentum suggest that momentum of the system is always conserved usnless no external force provided...
so we can say that the change in momentum of the ball is the momentum gain by the plate when ball strike with the base/plate......

 

[MAVtKnmJ]

Sounds good thanks!
Check your PM!

 

[MAVtKnmJ]

q4 b i) F= mv- mu / t (derived the formula using rate of change of momentum)

put the values in the formula u will get the ans...

F= m(v-u)/t
F= 35/1000(-4.5 -(3.5))/0.14 (when ball going upward took that direction velocity in negative)

F= -2

so magnitude = 2 n negative side shows the direction which we supposed earlier

so upwards......

Well I think you made a mistake ...

F = 35/1000 [{4.5 - (-3.5)}/0.14]
F= 2 N not -2 N

But thanks!

 

[MAVtKnmJ]

Q5 May/June 2004

The whole question is beyond me!

 

[MAVtKnmJ]

Anyone?