Answer:
Heat is very important in our daily life in warming the house, cooking, heating the water, and drying the washed clothes. The heat has many usages in the industry as making and processing the food and manufacture of the glass, the paper, the textile, and etc.
Explanation:
Answer:

Explanation:
The density of an object is given by

where
m is the mass of the object
V is its volume
In this problem,
m = 42 kg
V = 22 m^3
Substituting into the equation, we find the object's density:

Temperature doesn't do anything, the boiling point of stuff decreases. If you put water in a vacuum chainber then it will start to boil
To begin with, we can use the formula that links frequency, wavelength and velocity.
Because you already have the wavelength and the frequency, you just need to solve for velocity. You can do this by multiplying each side of the equation by frequency.
Therefore, 400 x 2.5 = 1000m/s.
Hope this helps :)