The two-second rule.
It is a common guideline to follow while driving.
It means that any given driver should be AT LEAST two seconds behind any vehicle that is driving in front of his vehicle. It might apply for any kind of vehicle.
Answer:
when work is done on the system or heat comes into the system
The answer is ultra violet radiation. From the air
Answer:
Q = 913.9 gpm
Explanation:
The Hazen Williams equation can be written as follows:

where,
P = Friction Loss per foot of pipe =
= 4 x 10⁻⁴
Q = Flow Rate in gallon/min (gpm) = ?
d = pipe diameter in inches = (400 mm)(0.0393701 in/1 mm) = 15.75 in
C = roughness coefficient = 100
Therefore,

<u>Q = 913.9 gpm</u>
Answer:
sum of these two vectors is 6.06i+3.5j-3.5i+6.06j = 2.56i+9.56j
Explanation:
We have given first vector which has length of 7 units and makes an angle of 30° with positive x-axis
So x component of the vector 
y component of the vector 
So vector will be 6.06i+3.5j
Now other vector of length of 7 units and makes an angle of 120° with positive x-axis
So x component of vector 
y component of the vector 
Now sum of these two vectors is 6.06i+3.5j-3.5i+6.06j = 2.56i+9.56j