Answer:
The number of calories needed is 6c.
Explanation:
The amount of energy 
needed to raise the temperature 
of water of mass 
is
where 
is the specific heat capacity of water.
Putting in numbers into equation (1), we get:
which is the number of calories needed.
Answer:
31.2 m/s
Explanation:
= Frequency of approach = 480 Hz
= Frequency of going away = 400 Hz
= Speed of sound in air = 343 m/s
= Speed of truck
Frequency of approach is given as
eq-1
Frequency of moving awayy is given as
eq-2
Dividing eq-1 by eq-2
= 31.2 m/s
The answer is A
Materials that are good conductors of thermal energy are called thermal conductors. Metals are very good thermal conductors. Materials that are poor conductors of thermal energy are called thermal insulators. Gases such as air and materials such as plastic and wood are thermal insulators
Answer:
d.) provides proteins for plants
Explanation:
