Question

A 20 N object displaces 2,000 ml of water. What is the buoyancy? The answer is 19.6 N. Can someone tell me how it got to be this number?

Answer 1

What are the units of 19.6??

Answer 2

oh sorry--it's Newtons.

Answer 3

Fb = rho x g x V

where Fb is Force of buoyancy, rho is density of the water, g is acceleration of gravity, and V is volume of the object.

rho = 1000 (for density of the water)
g = 9.8 (acceleration of gravity)
V = 2000 ml = 2 l = 2 dm^3 = 2 x 10 ^-3 m^3 (for volume of the object)

Fb = rho x g x V
Fb = 1000 x 9.8 x 2 x 10 ^-3
Fb = 9.8 x 2
Fb = 19.6 Newton

Answer 4

wait...how are you calculating the volume? and where did 1000 for the density come from? :(

Answer 5

for volume:
do you know that 1 L is equal to 1 dm^3???

for density of the water is usually used for the value of 1000, obtained by experimental results, You can get this value from the backyard of a physics textbook or on wikipedia

Answer 6

sorry if I'm difficult. I'm just having trouble grasping physics. I'm remembering the density of water now but I thought it was 1.0 g...and what is "dm" meant to stand for?

Answer 7

yes in another unit the density of the water is 1 gram/cm^3.., But if we do the conversion in units of kg/m ^ 3:

1 gram/cm^3 = (1 x10^-3 kg) / (1 x 10^-6 m^3) = 1x 10^3 kg/m^3 = 1000 kg/m^3

Answer 8

Sorry I forgot to tell you if the unit is for 1000 kg/m ^ 3

Answer 9

@craftshark98

Answer 10

thank you...I'm still trying to grasp this

Answer 11

welcome :)

Answer 12

@craftshark98 please check this out!

https://www.google.co.id/search?q=density+of+the+water&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:id:official&client=firefox-a

Answer 13

thanks :)

Answer 14

sorry i forgot to tell you that "dm" is Decimetre