Answer:
The value is 
Explanation:
From the question we are told that
The operating temperature is 
The emissivity is 
The power rating is 
Generally the area is mathematically represented as

Where
is the Stefan Boltzmann constant with value

So


The velocity of the ball when it was caught is 12.52 m/s.
<em>"Your question is not complete it seems to be missing the following, information"</em>,
find the velocity of the ball when it was caught.
The given parameters;
maximum height above the ground reached by the ball, H = 38 m
height above the ground where the ball was caught, h = 30 m
The height traveled by the ball when it was caught is calculated as follows;
y = H - h
y = 38 - 30 = 8 m
The velocity of the ball when it was caught is calculated as;

Thus, the velocity of the ball when it was caught is 12.52 m/s.
Learn more here: brainly.com/question/14582703
Answer:
Average speed will be 48.23 km/h
Explanation:
Let the distance up to hill is = d km
Speed when car goes to hill = 38 km/h
So time required 
Speed when car return from hill = 66 km/h
So time required to return fro hill 
Total time 
Total distance = d+d =2d
So average speed