Convection is the movement<span> of groups of molecules within </span>fluids<span> such as gases and liquids, including molten rock (rheid).</span>
Coal is burned to get energy. By burning coal, green houses gases like carbon dioxide, nitrogen oxides and suphur oxides are produced.
Rest of the energy sources given in the option are clean energies.
Answer is A.
Answer:
The velocity of the man from the frame of reference of a stationary observer is, V₂ = 5 m/s
Explanation:
Given,
Your velocity, V₁ = 2 m/
The velocity of the person, V₂ =?
The velocity of the person relative to you, V₂₁ = 3 m/s
According to the relative velocity of two
V₂₁ = V₂ -V₁
∴ V₂ = V₂₁ + V₁
On substitution
V₂ = 3 + 2
= 5 m/s
Hence, the velocity of the man from the frame of reference of a stationary observe is, V₂ = 5 m/s
Answer:
The density of the woman is 950.8 kg/m³
Explanation:
Given;
fraction of the woman's volume above the surface = 4.92%
then, fraction of the woman's volume below the surface = 100 - 4.92% = 95.08%
the specific gravity of the woman 
The density of the woman is calculate as;

Density of fresh water = 1000 kg/m³
Density of the woman = 0.9508 x 1000 kg/m³
Density of the woman = 950.8 kg/m³
Therefore, the density of the woman is 950.8 kg/m³