Unit: Centripetal Force
Year: 1997 Question#: 58
Question: Base your answers to questions 58-60 on the information and diagram below.
A 4.0-kilogram model airplane travels in a horizontal circular path of radius 12 meters at a constant speed of 6.0 meters per second.
What is the direction of the centripetal force on the airplane?
(1 ) north
(2 ) south
(3 ) east
(4 ) west
What is this question really asking?
Explanation by: Megan L
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Answer 1
north
INCORRECT
If the force were to the north the plane would accelerate in a straight line north. This would not create a constant speed in a circular path. return to top
Answer 2
south
INCORRECT
If the force were to the south it would decelerate the plane as the plane continued to travel to the north. This would not create a circular path and the speed would not remain constant. return to top
Answer 3
east
CORRECT
First : the definition of centripetal force is: a vector quantity directed toward the center of the circular path.
More conceptually : Without force the plane would continue traveling north at a constant velocity. The force to the east curves the plane's path without changing its speed. return to top
Answer 4
west
INCORRECT
An observer inside the plane would feel a "force" to the west. However, this is a ficticious force. When the eastern force on the plane causes the plane to accelerate eastward, the pelple inside the plane would, by the law of inertia, want to remain going straight. To them it will feel like a force is pushing them to the west. return to top
What's this question really asking?
If you know the direction of centripetal force. return to top
