Answer:
825 kgm⁻³
Explanation:
ρ = density of wood = ?
ρ' = density of water = 1000 kgm⁻³
V = volume of wood = 10 x 4 x 2 = 80 cm³ = 80 x 10⁻⁶ m³
V' = Volume of water displaced = 10 x 4 x 1.65 = 66 cm³ = 66 x 10⁻⁶ m³
Using equilibrium of force in vertical direction
Force of buoyancy = Weight of the wood
ρ' V' g = ρ V g
ρ' V' = ρ V
(1000) (66 x 10⁻⁶) = ρ (80 x 10⁻⁶)
ρ = 825 kgm⁻³
I don't personally know the answer, but this article should help!
http://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/what-is-a-black-hole-58.html
The amount of heat needed to increase the temperature of a substance by

is given by

where
m is the mass of the substance

is its specific heat capacity

is the increase of temperature
The sample of silver of our problem has a mass of

. Its specific heat capacity is

and the increase in temperature is

Therefore, the amount of heat needed is
Answer:
Respiration
Explanation:
The lungs and respiratory system allow us to breathe. They bring oxygen into our bodies (called inspiration, or inhalation) and send carbon dioxide out (called expiration, or exhalation). This exchange of oxygen and carbon dioxide is called respiration.