CHAPTER 9

What is the mass of the block floating in water?

10 cm

10 cm

25 cm

Wblock = Fbuoyant

mg = Vg

m = (1000) ½(.25)(.10)(.10)Volume of block

m = 1.25 kg

What is the mass of the cylinder floating in oil?

Wcylinder = Fbuoyant

mg = Vg

m = (926) ¾ (.12)(.03)2

Volume of cylinder

r = 3 cm L = 12 cm

= 926 kg/m3 m = .236 kg

What % of a solid cork ( = 240 ) will float below the surface of water?

Wcork = Fbuoyant

mg = Vgcork =

mcork

Vcork

cork Vcork = (water)(x)Vcork

corkwater

= x

2401000

= .24 = 24%

For ONE side

2 MASSLESS SIDES & BOTTOM!

The thick walls are made of Copper ( = 8930). How wide must the box be to float in water?

5 cm

24 cm

30 cm

x?

Wbox = Fbuoyant

mg = Vgside = mside

Vside

8930 = m

(.24)(.30)(.05)

m = 32.14 kg

64.3 = 1000 (.30)(.24)x

x = .893 m