What is the volume of a cylinder that has a radius of 3 cm and a height of 10 cm?
Volume = πr2 x h
V= 3.14x (3cm x 3cm) x10cm
V=282.6 cm3
3cm x 3cm = 9cm2
9.0cm2
X 3.1428.26 cm2 x 10 cm282.6cm3
r= 3cmh= 10cm
Aim – Why do things float or Sink?
Buoyancy
• Buoyancy is the force in a liquid or gas that pushes upwards. The opposite of gravity!
Buoyancy Gravity
A Nun Buoy
Matter can have
• Positive buoyancy - it floats
• Negative buoyancy – it sinks
• Neutral buoyancy – it “Flinks”
• Positive Buoyancy • The force of buoyancy is greater than the force of gravity!
• Negative Buoyancy • The force of gravity is greater than the force of buoyancy!
Neutral Buoyancy • The force of gravity is equal to the force of buoyancy!
Fluids with Different Densities(fluids include liquids and gases)
1.0 g/cm3 13.5 g/cm3 0.00018 g/cm3
Sink or float in Water (1.0 g/cm3 )?
1. Silver……………………….10.40 g/cm3 2. Douglass fir……………….0.56 g/cm3 3. Submarine ………………. 1.0 g/cm3
Sink or float in Water ?
1. Salt………………………….2.200 g/cm3 2. Maple………………………0.69 g/cm3 3. Ebony……………………..1.20 g/cm3 4. ZBT ………………………….1.00000009 g/cm3 5. XBT …………………………0.99999999 g/cm3
Sink or float in Gasoline (0.72 g/cm3 )?
6. Balsa………………………0.12 g/cm3 7. Maple………………………0.69 g/cm3 8. Ebony……………………..1.20 g/cm3 9. White Pine…………………0.43 g/cm3 10. ABT …………………………0.72 g/cm3
• A sphere has a volume of 38.2 cm3. If it flinks in water, what is its mass?