Let F = the downstream speed of the water.
<span>Then the boat's upstream speed is: 15 - F </span>
<span>The boat's downstream speed is: 15 + F </span>
<span>Assume both the journeys mentioned take T hours, then using "speed x time = distance" we get: </span>
<span>Downstream journey: (15 + F)T = 140 </span>
<span>Upstream journey: (15 - F)T = 35 </span>
<span>Add the two formulae together: </span>
<span>(15 + F)T + (15 - F)T = 140 + 35 </span>
<span>15T + FT + 15T - FT = 175 </span>
<span>30T = 175 </span>
<span>T = 35/6 </span>
<span>Use one of the equations to find F: </span>
<span>(15 + F)T = 140 </span>
<span>15 + F = 140/T </span>
<span>F = 140/T - 15 </span>
<span>F = 140/(35/6) - 15 </span>
<span>F = 24 - 15 </span>
<span>F = 9 </span>
<span>i.e. the downstream speed of the water is 9 kph </span>
<span>Therefore, the boat's speed downstream is 15 + F = 15 + 9 = 24 kph.
the answer is: *24kph*</span>
PART A)
As we know that energy of light depends on its wavelength and frequency as following formula

now we know that wavelength of blue light is less than the red light so here energy of blue light will be more
also we know that

so here if wavelength is smaller for blue light so its frequency will be high and the speed of both light will be same in same medium
PART B)
Since we know that frequency of blue light is more than red light as well as wavelength of blue light is less than the wavelength of blue light so here blue light will have more energy
When blue light and red light strike the metal surface then due to more energy of blue light it will release some loosely bonded electrons from metal surface which will contribute in current.
here if we increase the intensity of light then the number of photons that contain the blue light of certain energy will be more and that will contribute more current
So here quantification help as we know that due to quantization only certain frequency or energy will lead to eject electron so all colours will not give this current
I don’t know, which statement ahh I see white screen lol
Answer:
The Hydrostatic force is 
The location of pressure center is
Explanation:
From the question we are told that
The height of the gate is 
The weight of the gate is 
The height of the water is 
The density of water is 
Note used
for height of water and height of gate immersed by water since both have the same value
The area of the gate immersed in water is mathematically represented as

substituting values


The hydrostatic force is mathematically represented as

Where


So


The center of pressure is mathematically represented as

Where
is the moment of inertia of the gate which mathematically represented as

The
is the height of gate immersed in water
Thus

