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Numerade Educator



Problem 18 Easy Difficulty

An extraterrestrial spaceship is moving away from the earth after an unpleasant encounter with its inhabitants. As it departs, the spaceship fires a missile toward the earth. An observer on earth measures that the spaceship is moving away with a speed of 0.600$c .$ An observer in the spaceship measures that the missile is moving away from him at a speed of 0.800$c .$ As measured by an observer on earth, how fast is the missile approaching the earth?


$0.385 c$


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Video Transcript

The Observer on the spaceship measures the speed of the Messiah relative to the ship. Be prime X equal minus 0.8 times see, and the other observer measured the speed of the rocket ship related to up to be u is equal to 0.6 time. See, So now we need to solve for the X And we know from the Normans transformations that deep thanks is equal to the ex prime plus you all over one bless you times vi ex prime divided by sea squid and weaken some values into this since they'll know So this is minus 0 28 c for me, explain. Let's zero or in six time see for you over one less zero point six. What's abide by minus 0.8. We get these two terms by simply fine you be prime overseas Square Indians were left minus zero 0.2 times this beautiful ICTSI divided by 0.5 to and hence we get an answer off a minus zero when 85 times seat. That means that the speed off the missile in the earth's frame is 0.385 10 c