Answer:
a. speed, v = 0.97 c
b. time, t' = 20.56 years
Given:
t' = 5 years
distance of the planet from the earth, d = 10 light years = 10 c
Solution:
(a) Distance travelled in a round trip, d' = 2d = 20 c = L'
Now, using Length contraction formula of relativity theory:
(1)
time taken = 5 years
We know that :
time = 
5 =
(2)
Dividing eqn (1) by v on both the sides and substituting eqn (2) in eqn (1):
Squaring both the sides and Solving above eqution, we get:
v = 0.97 c
(b) Time observed from Earth:
Using time dilation:


Solving the above eqn:
t'' = 20.56 years
Angular momemtum : mass * tangential speed * distance to the center = 50*2.1*3.6=37800 J.s
Anton Von Leeuwenhoek, in the early 1600s, saw these tiny microbes and called them "animalcules" and "wee beasties".
Answer:
Leaves are the primary source of photosynthesis. Leaves are also have a vital function in plant processes like transpiration and guttation. I hope it helps:)
Heat absorbed by the solar collector = Area*Irradiance = 5.3*995 = 5273.5 W
Heat Q in joules absorbed in t hours = Heat used to heat water. That is,
5273.5*t = mCΔT; where mass = volume*density = 1*1000 = 1000 kg
Therefore;
5273.5t = 1000*4186*(65-20) = 188370000
t = 188370000/5273.5 = 35720.11 seconds = 35720.11/(60*60) hours ≈ 9.92 hours.
It will take approximately 9.92 hours.