99% of the earth´s atmosphere by mass is made up of only these elements: Nitrogen and oxygen.
Answer: B) Nitrogen and oxygen.
Again I think you did not give the right constants. So I would use the correct constants for mass of moon and distance from earth to moon.
<span>The formula for force of attraction between any two bodies in the universe
F = GMm / r^2. (Newton's Universal law of Gravitation).
G = Universal gravitational constant, G = 6.67 * 10 ^ -11 Nm^2 / kg^2.
M = Mass of Earth. = 5.97 x 10^24 kg.
m = mass of moon = 7.34 x 10^22 kg.
r = distance apart, between centers = in this case it is the distance from Earth to the Moon
= 3.8 x 10^8 m.
(Sorry I could not assume with the values you gave, they are wrong, and if we use them we would be insulting Physics).
So F = ((6.67 * 10 ^ -11)*(5.97 x 10^24)*(7.34 * 10^22)) / (3.8 x 10^8)^2.
Punch it all up in your calculator.
I used a Casio 991 calculator, it should be one of the best in the world.Really lovely calculator, that has helped me a lot in computations like this. I am thankful for the Calculator.
F = 2.0240 * 10^ 20 N.
So that's our answer.
Hurray!!</span>
Answer: 56994 miles
Explanation:
Given : Toby's Trucking Company determined that on an annual basis, the distance traveled per truck is normally distributed with

Standard deviation : 
Let a be the distance traveled by at least 72% of the trucks.
Let X be the random variable that represents the distance traveled by a truck
Then 
The critical value corresponds to p-value 0.72 :
Also, 

Hence, 56994 miles will be traveled by at least (equal to and more than) 72% of the trucks .
Answer:
Answer 3: When a balloon goes up higher in the air, its size will increase. Since there's less air in the upper atmosphere, there's less stuff pushing back on the balloon, and hence the pressure is lower, which allows the balloon to expand
Answer: C
Explanation:
As the balloon rises, the gas inside the balloon expands because the atmospheric pressure surrounding the balloon drops. The atmosphere is 100 to 200 times less dense at the float altitudes than on the ground. and as the air is heated inside the balloon it causes it to rise upwards (because it is lighter than the cooler air on the outside). When the pilot needs to bring the balloon down again, he simply reduces the temperature of the air inside the balloon causing it to slowly descend.