| James and Sally were sitting in their family room one night. While James was watching T.V., his wife Sally was reading. All of a sudden, the power went out and James decided to go to bed, but Sally kept on reading. With no use of artificial light, Sally kept on reading. How? |
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| Sirius is one of the closest stars to the earth. It is 8.7 light-years away but is moving towards us at 8 km per second. Wolf is another of our closest stars and is 7.7 light-years away. It is moving AWAY from us at 13 km per second. When Wolf has travelled one light-year, what will be the closest star to the earth? |
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