Physics MCQs thread.

[Talha]

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 ...

 

[unique840]

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 ...

ans A hai?

 

[unique840]

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 ...

K.E = (1/2)*m*(v^2)
square root of (K.E*2)/m = v
sb options ki velocity nikalo. jo best estimate hai velocity ka wo ans hai.

 

[Talha]

these values of velocity r coming

A 3.16
B 10
C 31.6
D 100


so vats da answer??

 

[Talha]

Y da ans is 'B' and not 'A' ?

 

[unique840]

these values of velocity r coming

A 3.16
B 10
C 31.6
D 100


so vats da answer??

phle batao ms ka kia answer hai? n mera to kch aur cuming
A 10
B 100
C 1000
D 10000
:%)
wese jo b hai, 10 wala ans hona chahiye. cox baqi sb normal human speeds nae hain

 

[unique840]

Y da ans is 'B' and not 'A' ?

same rxn. acceleration is constant throughout. its nt velocity k maximum height par 0 hojaye

 

[Talha]

Plz explain how ans is 'C' ?

 

[Talha]

Plz sum1 explain dis?

 

[unique840]

Plz explain how ans is 'C' ?

power is energy/time
max power means max gradient (energy/time)
max gradient is in time 2-3 seconds
(40-10)/(3-2)

 

[Talha]

Help me out at dis!

 

[Talha]

Helppp... Explain!!

 

[Talha]

Help me plzzz!!!

 

[unique840]

Helppp... Explain!!

iska answer phle given hai. chek it out

 

[unique840]

Help me out at dis!

iska answer C hai?

 

[Talha]

no its D

 

[unique840]

no its D

han sorry its D. power of P n Q at 0.5A is V*I. that is 0.5*2 for P n 0.5*4 for Q. u will get the answer

 

[Talha]

I managed to find the answer as efficiency doesnt have any unit so SI unit of both denominator and numerator cancel out
I know this isnt the right way to answer the mcq someone pls explain it in details...... ThNx Xhazemx for the previous answer...

Dude in my opinion it wud be like dis... efficiency= output energy / input energy or simply as final energy/ initial energy

so workdone in moving up = Fs
gravitational potential energy gained = mgh = mg s sin@

effeciency = mgssin@ / Fs which is equal to mg sin@ / F ... :beer: :Bravo: :good: :Yahoo!:

 

[unique840]

no its D

wese tm achi xplanation k liye zishi ya hassam se puch lena. mjhe achi xplanation dene nae ati

 

[ShootingStar]

Answer is D.. please explain..