The Student Room Group
Reply 1
Upthrust = Weight of Fluid Displaced
Hence , mass of water displaced = density * volume = (1000) * (4/3 pi (1/100)^3)
Hence weight displaced = mass * g = (1000) * (4/3 pi (1/100)^3) * 9.81 = Upthrust

Coefficient of visc needed only for drag force....

Upthrust + Drag = Weight of ball
[at terminal velocity]
antonfigo
Upthrust = Weight of Fluid Displaced
Hence , mass of water displaced = density * volume = (1000) * (4/3 pi (1/100)^3)
Hence weight displaced = mass * g = (1000) * (4/3 pi (1/100)^3) * 9.81 = Upthrust

Coefficient of visc needed only for drag force....

Upthrust + Drag = Weight of ball
[at terminal velocity]
hmm the answer should be 5.1 x 10^-3.

is anything supposed to be done with the steel density value?
Reply 3
5.1x10^-3 or 4.1x10^-3
Remember to convert 1 cm to 1/100 m

No...Steel density value is not needed for upthrust...but we need steel ball's volume which is equal to volume of water displaced...
antonfigo has used 1cm in the calculation, but this is the diameter of the sphere. The formula requires the radius; half of this.
Reply 5
Stonebridge
antonfigo has used 1cm in the calculation, but this is the diameter of the sphere. The formula requires the radius; half of this.


Oh yea!
I overlooked that :P ...now theres the real answer
Reply 6
1. Calculate the volume of the displaced liquid (volume of the block or object)
2. Calculate the mass of the displaced liquid using the formula=density x volume
3. Calculate the weight of the displaced liquid using the formula weight=massx10
Always write it down in Newton or N in kilograms so if the answer is 1.0x20=20grams its 0.020 kg then you use the formula weight = massx10 so the answer is: 0.20N
Original post by Ripiramon
1. Calculate the volume of the displaced liquid (volume of the block or object)
2. Calculate the mass of the displaced liquid using the formula=density x volume
3. Calculate the weight of the displaced liquid using the formula weight=massx10
Always write it down in Newton or N in kilograms so if the answer is 1.0x20=20grams its 0.020 kg then you use the formula weight = massx10 so the answer is: 0.20N


Welcome to TSR physics.

Thanks for this.

This thread was started in 2010 and is now closed.