(a) The distance to a star is approximately 6.90*10 18 m. If this star were to b
ID: 2047487 • Letter: #
Question
(a) The distance to a star is approximately 6.90*1018 m. If this star were to burn out today, how long from now would we see it disappear?
Answer in years.
(b) How long does it take for sunlight to reach Uranus?
Answer in minutes
(c) How long does it take for a microwave radar signal to travel from the Earth to the Moon and back?
Answer in seconds.
(d) How long does it take for a radio wave to travel once around the Earth in a great circle, close to the planet's surface?
Answer in seconds.
(e) How long does it take for light to reach you from a lightning stroke 10.3 km away?
Answer in seconds.
Explanation / Answer
a) time to disappear= (6.9*10^18)/(3*10^8) * 60*60*24*365 = 729.3 yrs b) Uranus is approx. 1.78 billion miles from the sun and light travels at approx. 186000 miles a second. time taken= 1.78 billions / 186000*60 = 160 min. c) 2.56 sec d) find earths circumference in meters... C = 2PiR 2 x 3.14 x 6378 km x 1000 m/km = 4 x 10*7 m radiowave velocity = 3 x 10^8 m/s time = distance/speed = 4 x 10^7/3 x 10*8 = 0.134 sec e.)again, time = distance/speed 10.3 km/3 x 10^5 km/s = 3.43 x 10^-5 sec
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.