Construct a vector diagram. It will be a right-angled triangle. One vector (the hypotenuse) represents the heading of the boat, one represents the current and one represents the resultant speed of the boat, which I'll call x. Their magnitudes are 20, 3 and x. Let the required angle = theta. We have:
<span>theta = arcsin(3/20) = approx. 8.63° </span>
<span>The boat should head against the current in a direction approx. 8.63° to the line connecting the dock with the point opposite, or approx. 81.37° to the shore line. </span>
<span>x = sqrt(20^2 - 3^2) </span>
<span>= sqrt(400 - 9) </span>
<span>= sqrt 391 </span>
<span>The boat's crossing time = </span>
<span>0.5 km/(sqrt 391 km/hr) </span>
<span>= (0.5/sqrt 391) hr </span>
<span>= approx. 0.025 hr </span>
<span>= approx. 91 seconds</span>
Answer:

Explanation:
From the question we are told that:
Height 
Radius 
Height of water 
Gravity 
Density of water 
Generally the equation for Volume of water is mathematically given by


Where
y is a random height taken to define dv
Generally the equation for Work done to pump water is mathematically given by

Substituting dv


Therefore




![W=3420.84*0.25[2401-65536]](https://tex.z-dn.net/?f=W%3D3420.84%2A0.25%5B2401-65536%5D)


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The muscular system brings strength and endurance to the body. It helps us perform everyday activities. As well as soaks up water to keep us hydrated longer.
As we know that in transformers we have

here we know that



now from above equation we will have


