Explanation:
Given that,
Average power of sun 
We need to calculate the intensity of light at Earth's position
Using formula of intensity

Where, I = intensity
P = power
Put the value into the formula


So, The intensity is 1347.616 W/m².
(A). We need to calculate the pressure on a solar sail due to the light of the sun if it's fully reflective
Using formula for fully reflective

Put the value into the formula


(B). We need to calculate the pressure on a solar sail due to the light of the sun if it's fully reflective
Using formula for fully absorptive



Hence, This is the required solution.
Answer:
Part 1)
Boat A will win the race
Part 2)
Boat A will win the race by 48 km as the 2nd boat will reach the other end while boat A will just touches the finish line
Part 3)
average velocity must be zero
Explanation:
As we know that the distance moved by the boat is given as

now the time taken by the boat to move to and fro is given as



Time taken by Boat B to cover the distance


Part 1)
Boat A will win the race
Part 2)
Boat A will win the race by 48 km as the 2nd boat will reach the other end while boat A will just touches the finish line
Part 3)
Since the displacement of Boat A is zero
so average velocity must be zero
Explanation:
Given that,
Wavelength = 6.0 nm
de Broglie wavelength = 6.0 nm
(a). We need to calculate the energy of photon
Using formula of energy



(b). We need to calculate the kinetic energy of an electron
Using formula of kinetic energy


Put the value into the formula


(c). We need to calculate the energy of photon
Using formula of energy



(d). We need to calculate the kinetic energy of an electron
Using formula of kinetic energy


Put the value into the formula


Hence, This is the required solution.
The work done when a spring is stretched from 0 to 40cm is 4J.
What is work done?
Work done is the magnitude of force multiplied by displacement of an object. It is also the amount of energy transferred to an object when work is done on that.
The work done on the spring to stretch to 40cm is,
F = kx
where F is force, k is force constant.
k = F / x = 10 N / 20 * 10^-2 m = 50 N/m
W = 0.5 * k * (x)^2
where W = work done, k = force constant.
W = 0.5 x 50 x (40 x 10^-2)^2 = 4 J.
Therefore, the work done on the spring when it is stretched to 40cm is 4J.
To learn more about work done click on the given link brainly.com/question/25573309
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