physics mcq help needed! urgent!

[nid404]

nv 2007 q 2,11 and 40..??
plzz someone?

2) approx diameter of an atom/ion is to the power of 10^-15 ...you have no choice but to know this

11) B  Because there also a normal contact force acting on the wheels vertically up. And there's the forward force by the engine. Their resultant would be B

[ifraha18]

bt the answer fr 2 is A!!!10^-15..
and answer fr 40 is A..alpha particle.?

[nid404]

bt the answer fr 2 is A!!!10^-15..
and answer fr 40 is A..alpha particle.?

oops my bad. A it is...I edited my post. Well what i wanted to say was you gotta memorize it

[ifraha18]

wht about 40???

thnkss a bunc..

[nid404]

yup for the 40th one...i will look...I'm a lil confused myself...

[highly_ambitious]

guyz, may/june 2002 q9...can't get the question. plz help.!

elastic collision mean that spheres should stick together n move in the direction of the heavier mass? innit?

[nid404]

huh?

The ball is first moving towards the racket with a velocity of 20m/s. The ball hits the racket and moves in the opp direction with a velocity of 30m/s

so the change in momentum is given by

mv-mu

v=30m/s
u=-20m/s (- sign cause it's in the opp direction)

30X0.1kg-(-20X0.1kg)=5kgm/s

so B

[highly_ambitious]

huh?

The ball is first moving towards the racket with a velocity of 20m/s. The ball hits the racket and moves in the opp direction with a velocity of 30m/s

so the change in momentum is given by

mv-mu

v=30m/s
u=-20m/s (- sign cause it's in the opp direction)

30X0.1kg-(-20X0.1kg)=5kgm/s

so B

can  u tell me where is this question?

[nid404]

you said  june 09 Q9 right?

[highly_ambitious]

you said  june 09 Q9 right?

no yarr...i said m/j 2002 q9.

[nid404]

no yarr...i said m/j 2002 q9.

oiii...my bad.

well for that question

they won't stick together, they possibly can't because they both have the same mass and same velocity but are moving towards each other. For them to stick, either one has to have a greater mass or a greater velocity

So B is the answer
because in an elastic collision, k.e is conserved

before collision k.e= 1/mv2 + 1/2 mv2= mv2
so after collision this k.e will be conserved.

The other statements ain't possible either

[halosh92]

oiii...my bad.

well for that question

they won't stick together, they possibly can't because they both have the same mass and same velocity but are moving towards each other. For them to stick, either one has to have a greater mass or a greater velocity

So B is the answer
because in an elastic collision, k.e is conserved

before collision k.e= 1/mv2 + 1/2 mv2= mv2
so after collision this k.e will be conserved.

The other statements ain't possible either

i have a question.
for the ke..shouldnt we consider their opposite directions here???
so one would be (+) and the other (-) ??

[highly_ambitious]

oiii...my bad.

well for that question

they won't stick together, they possibly can't because they both have the same mass and same velocity but are moving towards each other. For them to stick, either one has to have a greater mass or a greater velocity

So B is the answer
because in an elastic collision, k.e is conserved

before collision k.e= 1/mv2 + 1/2 mv2= mv2
so after collision this k.e will be conserved.

The other statements ain't possible either

yeah right!...Thanks

same paper q28..i always get confused in question which relate to wave. In this question too i got stuck. In the fig, point X is shown above 'O' so the path difference should be 'n' whole number. Therefore, we get a bright fringe. Thus the path difference should be S₂X - S₁X = lambda .

then why is the answer C..can't get!!

[nid404]

i have a question.
for the ke..shouldnt we consider their opposite directions here???
so one would be (+) and the other (-) ??

energy is a scalar quantity

[nid404]

yeah right!...Thanks

same paper q28..i always get confused in question which relate to wave. In this question too i got stuck. In the fig, point X is shown above 'O' so the path difference should be 'n' whole number. Therefore, we get a bright fringe. Thus the path difference should be S₂X - S₁X = lambda .

then why is the answer C..can't get!!

I'm not too good with waves but...

there's a formula for such type of question



for destructive interference the phase difference should be

so if you rearrange the eqn (i substituted phase difference as

=

path difference= S2X-S1X

so you get

=