Qualification > Sciences
Edexcel PHYSICS Doubts
dk bose:
--- Quote from: astarmathsandphysics on December 24, 2011, 07:15:56 pm ---1)cos fresh water is less dense than salt water so sho upthrust is less so ship is lower in the waer
2)V=mass/density=0.180/8000=2.25*10^-5 m^3
Upthrus=weight of oil displaced =density*volume*g=800*2.25*10^-5=0.018g
tension=wieght-upthrust=0.180g-0.018g=1.5876N
3)fins/wings/shark skin
4)is this an english question?
5) would be quicker since water molecules move faster.
--- End quote ---
The 4th question is not an english question,its a question from the Edexcel AS physics textbook from materials chapter.
dk bose:
--- Quote from: dk bose on December 21, 2011, 11:04:12 pm ---1)A capacitor charges through a 0.22 M ohm resistor. Calculate the capacitance if the time taken for it to reach full charge is 5 minutes.
2)A 47*10^-6 F capacitor is charged to a potential difference of 15V and then discharged through a 100 k ohm resistor. How long does it take for half of the energy stored in the capacitor to have dissipated in the circuit?
3)Mains-operated power supplies have large-value capacitors to help keep the output voltage constant. In
a full wave rectified supply, without a capacitor the output falls to zero every 10 ms. If the output must be
maintained at a value at least 90% of its maximum value when a load of 1.0 k ohm is connected to the output
terminals, show that the minimum capacitance needed in the power supply circuit is about 100*10^-6F.
--- End quote ---
the first question is not done!! plzz solve it and post the solutions as fast as possible!!!!
astarmathsandphysics:
To answer the first I need more information.
dk bose:
what information? i copied the whole question and posted it here.just try to solve the sum and post the solution as fast as possible!!!!!
astarmathsandphysics:
Like working voltage.
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