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An Earth starship has been sent to check an Earth outpost on the planet P1407, whose moon houses a battle group of the often hostile Reptulians. As the ship follows a straightline course first past the planet and then past the moon, it detects a high-energy microwaveburst at the Reptulian moon base and then, 1.10 s later, an explosion at the Earth outpost, which is 4.00xx10^(8) m from the Reptulian base as measured from the ship's reference frame. The Reptulians have obviously attacked the Earth outpost, and so the starship begins to prepare for a confrontation with them. What is the meaning of the minus sign in the value for Deltat' ? |
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Answer» Solution :Reasoning: We must be consistent with the notation we set up in part (a). Recal how we ORIGINALLY defined the time interval between burst and explosion: `DELTAT=t_(e )-t_(b)= +1.10s`. To ber consistent with that choice of notation, our definition of `Deltat. ` must be `t._(e )-t._(b)`, thus, we have found that `Deltat.=t._(e )-t._(b)= -1.04s`. The minus sign here tells US that `t._(b) gt t._(e )`, that is, in the planet-moon reference frame, the burst OCCURRED 1.04s after the explosion, not 1.10 s before the explosion as DETECTED in the ship frame. |
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