Physics MCQs thread.

[unique840]

Answer is D.. please explain..

iski xplanation pehle given hai pg 27 par

 

[ShootingStar]

Answer is D.. please explain..

iski xplanation pehle given hai

Konsay page pe? 42 pgs hogai hain is thread ke.... yaar explain kardo..

 

[unique840]

Answer is D.. please explain..

iski xplanation pehle given hai

Konsay page pe? 42 pgs hogai hain is thread ke.... yaar explain kardo..

yar it was jus written that "the vertical component of acceleration is ALWAYS CONSTANT .. g = 9.81 ms^-2"
"vertical component of velocity decreases as object is moving along the given path, becomes zero at the maximum height and then increases down the path. horizontal component of velocity is always constant"

 

[Talha]

Freaking confusing.. Plz help!!!

 

[ShootingStar]

doubts!!

 

[ShootingStar]

another one!

 

[yubakkk]

An Olympic athlete of mass 80 kg competes in a 100m race.
What is the best estimate of his mean kinetic energy during the race?

A 4 x 10^2 J
B 4 x 10^3 J
C 4 x 10^4 J
D 4 x 10^5 J

Explain plz ...

remember that mass of athlets is approx. 80 kg and his\her velocity is 10m/s

 

[yubakkk]

what 2 do yar till 8 june///// boring........................

 

[melon159]

http://www.xtremepapers.me/CIE/Internat ... 7_qp_1.pdf
no.23....help!!!

 

[ninjas4life]

5 The power loss P in a resistor is calculated using the formula P = V 2/R.
The uncertainty in the potential difference V is 3% and the uncertainty in the resistance R is 2%.
What is the uncertainty in P?
A 4% B 7% C 8% D 11%

 

[yubakkk]

uncertainty in p =2*uc.in v+uc. in r
so us in p=2*3+2=8%
c is wright

 

[melon159]

helpp

 

[ninjas4life]

is there a general formula for percentage uncertainites?

 

[melon159]

 

[yubakkk]

is there a general formula for percentage uncertainites?

you should always add the uncertiniy
if
x=y^2+z then
uncertiniy in x =2*uncertiniy in y+uncertiniy in z
it is only the formula

 

[yubakkk]

for melon q.
A=2m
lamda(l)=50m
so v=l*f
hence f = 0.16
now max v =2*pi*2*0.16=2.01
so max ke =0.5*m*2.01^2
you wil gwt ans 4 mj

 

[hassam]

D & C

1st one its C and second also C...1ST ONE...U ONLY NOTICED normal reaction...theres also frictionb/w ladder and wall

 

[nidzzz09]

Okay i m late nut i wannnna know how do yu call it Accurate

 

[hassam]

WHERES THAT QUESTION......melon
u find frequency using f=v/lambda...it is .16 Hz...now find spped...using max. a i.e 2 cos every patricle cn reach it as it is a progressive wave...now apply k.e formula
and u shud get it 4 mJ

 

[xHazeMx]

Help me plzzz!!!

is it B ?