Question

3) A geosynchronous satellite travels around the earth once every 24 hours (thereby always staying above the same point on the earth's surface). Such satellites are at a distance of 4.23x 107 m from the center of the earth. How fast is such a satellite moving with respect to the earth? A) 3.08 x 103 m/s B) 5.67 x 104 m/s C) 5.55 x 102 m/s D) 7.17 x 105 m/s E) 240 x 103 m/s 4) A long distance swimmer is able to swim through still water at 4 km/h. She wishes to try to swim from Port Angeles, WA due north to Victoria, B.C, a distance of 50 km. An ocean current flows through the Strait of Juan de Fuca from west to east at 3 km/h. In what direction should she swim to make the crossing along a straight line between the two cities? A) 49 west of north B) 41 west of north C) 41° east of north D) 37 east of north E) 37 west of north

Answer 1

Concept: for the first problem use the time period of a satellite in orbit and for the second, use the concept of relative velocity in two dimensions as shown below

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