Physics MCQs

[halosh92]

Yeh of course u should use the diameter because its the perpindicular distance between the two forces.If u use the radius u would get the wrong answer
if u can explain the method for 22 plz i still have difficulty with it thanx

thx

ok c:
Y.M=STRESS/STRAIN
stress=F/A
stress=F/pie (d/2)^2
stress=20/ ( pie *(([5*10^-4])/2)^2)
strain= stress/Y.M
strain = stress(the value we calculated above substitute here)/ (2*10^11)
starin= answer A
basically the question is asking for estension/original length which is nothing but strain

got it?

[hesho21]

yeh got it , Thanks soo much 

[yasser37]

Thanks m8

this is all left that I didn't know

Hi guys

so I've done past papers and I have some doubts


Nov 01
37
June 02
14
18
23
35
40

NOV 02
24
34
36
40

June 03
5
22

Nov 03
13
24
31
40

June 04
18
26


Nov 04

11
18 ( what is the equation used here? )
20
37


June 05
4
13

Nov 05
34

??

[nid404]

June 02

14) Pressure=Force/area
Pressure= P_b-P_t

therefore Force= ( P_b-P_t) a

18) consider p.e at P as X. So p.e at Q is (X-50) J
k.e at P is 5kJ...that means p.e+k.e at P is X+5 kJ and W.d against friction is 10kJ. therefore at the lowest point it has (X+5)-10 kJ of energy=X-5 kJ
p.e at Q is X-50...the difference is....k.e at Q is given by
X-5-(X-50)= 45kJ

23) Young's Modulus= Stress/Strain= 60/x/ 8/l   where x is the cross-section area and l is the original length
Young's modulus is therefore= 60l/8x
Now when area of cross-section is 4 times.
60l/4xe (e is the extension) should be equal to 60l/8x
Also though the length is doubled
which means
60X2l/ 4xe= 60l/8x
120l/4xe=60l/8x
e=4mm

35) voltage splits in series circuit depending on the ratio of resistance.
 
R3=2V
between R2 and R3= 3-2=1V
so R1= 5-(r3+r2)
       =2 V

this means R1=R3

so answer is C

 40) Bh has 3 alpha particles + Md
so ^255+4+4+4₁₀₁₊₆Md

so neutrons= (255+12)-(107)
                =160

[zxcvbnm]

november 04, 18