Answer:
a) 4.9W b) 3.82W
Explanation:
Stefan-Boltzmann law of radiation formulae:
Q/t (W) = sigma* e*A*T^4
Sigma = 5.67*10^-8 j/sm^2K^4 (Stefano Boltzmann constant)
e = emissivity
T = absolute temperature in kelvin and A = area in m^2
a) Q/t = 140/10000(m^2) * 0.87* 5.67* 10^-8* (290^4) = 4.9W
b) without hair the
Q/t = 140/ 10000(m^2) *0.68* 5.67* 10^-8* (290^4)
= 3.82W
The net force with be 10 N east. As both boys are pushing a wagon to the same direction, you just add the numbers together. If the directions were opposite like if it was the boy pushing 6 N east and the other boy pushing 4 N west...then it would come out as 2 N east (you subtract and go to the direction with the biggest number) if you have any confusions, feel free to ask
Condensation must occur. Water droplets collect on the cold surface when warm/humid air is in contact with it.
i just took this test and got it right.
1.3 second of time will be required for reflected sunlight to travel from the Moon to Earth if the distance between Earth and the Moon is 3.85 × 105 km
<h3>
What is Speed ?</h3>
Speed is the distance travelled per time taken. It is a scalar quantity. And the S.I unit is meter per second. That is, m/s
In the given question, we want to find how much time is required for reflected sunlight to travel from the Moon to Earth if the distance between Earth and the Moon is 3.85 × 10^5 km.
What are the parameters to consider ?
The parameters are;
- The distance S = 3.85 ×
km
- The Speed of Light C = 3 ×
m/s
Speed = distance S ÷ Time t
Convert kilometer to meter by multiplying it by 1000
C = S/t
3 ×
= 3.85 ×
/ t
Make t the subject of formula
t = 3.85 ×
/ 3 × 
t = 1.2833
t = 1.3 s
Therefore, 1.3 second of time will be required for reflected sunlight to travel from the Moon to Earth if the distance between Earth and the Moon is 3.85 × 105 km
Learn more about Speed here: brainly.com/question/4931057
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