Answer:
Explanation:
Given that,
Frequency of radio signal is
f = 800kHz = 800,000 Hz.
Distance from transmitter
d = 8.5km = 8500m
Electric field amplitude
E = 0.9 V/m
The average energy density can be calculated using
U_E = ½•ϵo•E²
Where ϵo = 8.85 × 10^-12 F/m
Then,
U_E = ½ × 8.85 × 10^-12 × 0.9²
U_E = 3.58 × 10^-12 J/m²
The average electromagnetic energy density is 3.58 × 10^-12 J/m²
Answer:
0.4 m/s
Explanation:
Law of conservation of momentum tell us that the change in momentum of the hammer will be equal to the change in momentum of the astronaut
change in momentum of hammer = change in momentum of astronaut
2 kg (14 m/s - 0 m/s) = 70 kg * (v-0)
v = 0.4 m/s
From the point of view of the northern hemisphere:
The sun starts out the year at the Spring equinox, March 21,
Right Ascension 0, Declination 0.
3 months later, Summer solstice, June 21
RA = 6 hours, Dec. = +23.5°
3 months later, Fall equinox, September 21,
RA = 12 hours, Dec. = 0
3 months later, Winter solstice, December 21,
RA = 18 hours, Dec. = -23.5°
