physics question

mimmi

mimmi

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12. Answer is potential energy > kinetic energy! As he is falling, the potential energy in him is converted to kinetic energy as he comes closer to the earth! i dont know the exact reason but i look at this as a general 'rule' in physics

29. Answer is 5! ( i asked about this question with my teacher ) the black dots shows wires that are connected so if you dont see a dot where two different wires are meeting, its not connected! looking at the switches and tracing them to the power source and bulb shows that if the no 5 switch is closed the circuit gets completed but if some other switch is closed, you will also need to close another switch!
 
A

ahsan99

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alay said:
could someone pls explain question 12 and 29 please http://www.xtremepapers.net/CIE/Cambrid ... _qp_11.pdf
Click to expand...


these are from my paper :)
for qtn 12..remember that when speed is constant there is no change to/ from kinetic energy
because change from one form to another involves increase/decrease of K.e hence an increase or decrease in
speed..so D is the correct ans

qtn 29 is all abt obversation...actually apparently it seems that all the wires have been connected but in reality they arent
wires are only joint at the point where dots are shown...hence current from positive side of the battery will only light the bulb when 5th switch is pressed..so C..trace the path of current for each and you will come to know..for the rest wires are only
placed upon each other THEY ARENT CONNECTED..and so fr the passage of current more than one switch needs to closed
 
C

carolinetcw

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mimmi said:
12. Answer is potential energy > kinetic energy! As he is falling, the potential energy in him is converted to kinetic energy as he comes closer to the earth! i dont know the exact reason but i look at this as a general 'rule' in physics

29. Answer is 5! ( i asked about this question with my teacher ) the black dots shows wires that are connected so if you dont see a dot where two different wires are meeting, its not connected! looking at the switches and tracing them to the power source and bulb shows that if the no 5 switch is closed the circuit gets completed but if some other switch is closed, you will also need to close another switch!
Click to expand...

no kinetic energy because CONSTANT SPEED! correct answer is D , all loss in PE is changed to thermal energy.
 
bamteck

bamteck

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The Question no. 29 :: The answer is A.

Current is already flowing through the lamp.

Check Marking scheme and examiner's report [cambridge]. This may help u to understand it more clearly.
 
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