I think the correct answer would be D. The tap water in the experiment is one the three test conditions of the independent variable, the type of water. The independent variable in a experiment is the one being manipulated or the one being changed. In this case, it is the type of water.
The answer is D, the amount of energy stays the same.
Avogadro's number: 6.02 x 10^23 atoms is present in 1mol of a solid (i.e. 22, 400 cm3)
Hence, in 1 cm3, 6.02 x 10^23 /22400 atoms is present = 2 x 10 ^ 19 atoms.
Lift force exerted by the air on the rotors=143244 N
Explanation:
we use Newtons second law
F- (M+m)g=(M+m)a
F= lift force
m= mass of helicopter= 13000 Kg
M= mass of car= 2000 lb=907.2 kg
a= acceleration= 0.5 m/s²
g= acceleration due to gravity
F- (M+m)g=(M+m)a
F=(M+m)(a+g)
F=(13000+907.2)(0.5+9.8)
F=143244 N
