Answer:
L = W = 6.810 cm
H = 10.22 cm
Explanation:
given data
volume L W H = 474 cm³
sides of the box cost = 2 cent/cm²
top and bottom cost 3 cent/cm²
to find out
dimensions of the box that minimize the total cost of material use
solution
we know here L W H = 474
here L is length and B is width and H is height
so when we minimize the cost function
C( L, W, H ) = (2) 2 H ( L + W ) + (3) 2 L W
so put here H
substitute H =
we get
C( L, W ) = 1896 (
) + 6 LW
so
minimum cost will be when the two partial derivatives is 0
so
= 6W -
= 0
so
= 6L -
= 0
L = 
so
by solving above equation we get
L = W =
= 6.810 cm
and
H = 
H = 10.22 cm
The angular speed remained constant after twelve turns at 11 rad/s.
Explanation:
As per the Newtons equation of motion, the final velocity can be determined by using the below equation, provided ,the displacement and acceleration with initial velocity is given.

Since, the present case follows circular motion, the displacement will be equal to angular displacement. And the velocity is equal to angular velocity.
As the car revolves complete twelve turns, then the displacement will be zero, since the final position is equal to the initial position.
So,

Thus, the angular speed remained constant after twelve turns at 11 rad/s.
Answer:
Angle of Refraction = 28.9 degrees
Explanation:
<u><em>We'll use Snell's law for this. It's mathematical form is:</em></u>
=> 
Where 
=>
and
are the refractive indexes of the air and water respectively.
<u><em>Solution:</em></u>
=> 1 * sin (40) = 1.33 * sin(
)
=> sin
= 
=> sin
= 0.4821
=>
= 28.9 degrees