Physics MCQs thread.

[Hateexams93]

btw that last Q , i got one part but i can't understand the rest hold on i"ll upload

 

[Hateexams93]

so i don't know the rest ..can some1 help me ?

 

[yubakkk]

moment=f*perp. dist between line of action and pivot or from where u have taken moment
so here
take moment about any point let from upper f
w*a+f*h=w*2a its option a
if u take moment from cg
f*h/2+f*h/2=wa which is also same as option a

 

[yubakkk]

this cie compose wat a tricky question

 

[Hateexams93]

why it equals to 2Wa ? and what is cg ?

 

[yubakkk]

cg iz centre of gravityi.e middle w
perp. dist from upper f 2 lower f iz 2a

 

[Hateexams93]

from upper to lower f ithe distance is H , but not 2a ..i didn't get it

 

[yubakkk]

f u take moment from cg
f*h/2+f*h/2=wa which is also same as option a
have u get tis???? its sufficient////

 

[hassam]

some body asked wave questin...in which we had to tell which point will be moving up with max speed...so jxt rememba' this.....if a trough is aligned with crest then point at eq. position will be moving DOWN....for creast-trough vice versa...points at crest-trough are stationary and have max. acceleration...memorise it

 

[melon159]

which wave properties change when light passes from air to glass?
a. color and speed
b. frequency and wavelength
c. speed and wavelength
d. wavelength and color
???

 

[hassam]

c

 

[melon159]

how is that?? frequency is always constant??

 

[Hateexams93]

some body asked wave questin...in which we had to tell which point will be moving up with max speed...so jxt rememba' this.....if a trough is aligned with crest then point at eq. position will be moving DOWN....for creast-trough vice versa...points at crest-trough are stationary and have max. acceleration...memorise it

Hassam can u plz show it on the pic????? using paint or smth else , doesn't matter

 

[aliya_zad]

Pls help..

 

[Hateexams93]

Pls help..

ok here u know that speed V is in ms^-1 so check the units ..in this case g= ms^-2 and wavelenght is in metres so g* wavelenght = ms^-2 * M =m^2*s^-2, square root of which is ms^-1 ..same as V ( speed)

 

[hassam]

sqrt.(g* lamda).....chek its units ....u ll know WHY

 

[hassam]

 

[hassam]

 

[Hateexams93]

some body asked wave questin...in which we had to tell which point will be moving up with max speed...so jxt rememba' this.....if a trough is aligned with crest then point at eq. position will be moving DOWN....for creast-trough vice versa...points at crest-trough are stationary and have max. acceleration...memorise it

Hassam can u plz show it on the pic????? using paint or smth else , doesn't matter

should i wait or ask some1 else ?

 

[hassam]