An 80 kg astronaut has gone outside his space capsule to do some repair work. Un

Question

An 80 kg astronaut has gone outside his space capsule to do some repair work. Unfortunately, he forgot to lock his safety tether in place, and he has drifted 5.0 m away from the capsule. Fortunately, he has a 1000 Wportable laser with fresh batteries that will operate it for 1.0 h. His only chance is to accelerate himself toward the space capsule by firing the laser in the opposite direction. He has a 10-h supply of oxygen.

How long will it take him to reach safety?

Express your answer to two significant figures and include the appropriate units.

Already posted this once and got 8.76 hours which was an incorrect answer, someone please help

Already posted this once and got 8.76 hours which was an incorrect answer, someone please help

Explanation / Answer

Radiated power is given by:

Prad = I/c

Force is given by:

F = Prad*A = I*A/c = Pavg/c

Using force balance:

Fnet = F

m*a = Pavg/c

a = Pavg/(m*c)

a = 1000/(80*3*10^8) = 4.167*10^-8 m/sec^2

Now time taken will be given by:

d = u*t + 0.5*a*t^2

d = 5.0 m

t = sqrt (2*d/a)

t = sqrt (2*5/(4.167*10^-8))

t = 15491.31 sec = 4.30 hr

Please Upvote.

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