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Unformatted text preview: PHYS2010 EXAM 3, VERSION 0001, SPRING 2006 1 The following three questions refer to a satellite of mass m in a circular orbit at a height h above the earths surface. Assume h is on the order of a few hundred miles, so the satellite is free of any effects from the earths atmosphere. The earth has radius R E and mass M E . 1. The direction of the satellites acceleration is: A) Along the direction of the satellites velocity v . B) Straight up, away from the earth. C) Opposite the direction of the satellites velocity, i.e. along - v . D) Some other direction, but none of those mentioned. E) The acceleration is zero. The acceleration is straight down, toward the center of the earth. This is none of these answers. 2. The magnitude of the net force on the satellite is: A ) mg B ) GM E m R 2 E C ) GM E m ( R E + h ) 2 D ) gM E m ( R E ) 2 E ) None of these The only force acting on the satellite is the earths gravity, which has magnitude GM E m/ ( R E + h ) 2 because the satellite is a distance R E + h from the earths center. 3. The magnitude of the acceleration of the satellite is: A ) g B ) GM E m R E C ) GM E ( R E + h ) 2 D ) gM E ( R E ) 2 E ) None of these The satellites acceleration is F net /m , which is equal to GM E / ( R E + h ) 2 . For the following two situations, what can we assume about the acceleration of the mass? Remember that acceleration is a vector, so constant means constant in both magnitude and direction. 4. A mass m is glued to the rim of a merry-go-round of radius R and is spinning at a constant rate such that its period is T . Its acceleration is: A) Constant and zero B) Constant and nonzero C) Not constant D) Not enough information given The acceleration has constant magnitude but not direction. Therefore it is not con- stant . 5. A mass m is released from rest at a point 15,000 km above the surface of the earth. (The earths radius is 6,400 km.) It falls straight toward the center of the earth and burns up near the surface after falling for over an hour. While falling, its acceleration is: A) Constant and zero B) Constant and nonzero C) Not constant D) Not enough information given The acceleration has constant direction but not magnitude, since it travels over a distance that is significant compared to the earths radius. Therefore, the acceleration is not constant . PHYS2010 EXAM 3, VERSION 0001, SPRING 2006 2 6. An object of mass m rests without slipping on the rim of a merry-go-round spinning at constant angular speed, as shown: Which of the following free-body diagrams illustrates most closely the forces on the...
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