Physics: Post your doubts here!

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sara kamal

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TaffsAsLevel said:
for 32, resultant force is zero because it rotates at a constant speed because and anti clockwise because E is downward so downward is negative so it repels it and it became anti clockwise, C

For 23, try to compare both of the E for their respective length and radius then compare the multiples, I can't do the working its too long, answer B

For 20, E=mgx so g is the accelration due to gravity therefore g=E/mx or magnitude=E/mx and direction is toward earth but it says loses EPE so direction must be towards the right isn't it because it says P to Q. so A
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Thank you so much:)
 
S

sara kamal

Messages
94
Reaction score
66
Points
28
TaffsAsLevel said:
for 32, resultant force is zero because it rotates at a constant speed because and anti clockwise because E is downward so downward is negative so it repels it and it became anti clockwise, C

For 23, try to compare both of the E for their respective length and radius then compare the multiples, I can't do the working its too long, answer B

For 20, E=mgx so g is the accelration due to gravity therefore g=E/mx or magnitude=E/mx and direction is toward earth but it says loses EPE so direction must be towards the right isn't it because it says P to Q. so A
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Yousif Mukkhtar said:
Q32:
Resultant force is zero as forces acting on Q and -Q are same in magnitude but opposite in directions. Now you can see that both forces form a couple which turns the rod anticlockwise.

Q23:
Both wires are of the same material which is steel so both Young modulus are exactly same. DImensions do not matter when materials are exactly same
Q20:
Formula for PE is mgh

Here E is the potential energy lost. So:
pe=mgh
E=mgx
g=E/mx and this happens in the right direction. If it is in the opposite direction pe is gained not lost![/quo


Jazak Allah Khairan!
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