Unit: mechanics
Year: 1988 Question#: 9
Question: Which combination of graphs best describes free-fall motion? [Neglect air resistance.]
(1 ) A and C
(2 ) B and D
(3 ) A and D
(4 ) B and C
What is this question really asking?
Explanation by: Esy C
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Answer 1
A and C
INCORRECT
Both graphs incorrectly illustrate each relationship; A is wrong because for a falling object distance increases at an increasing rate and C is wrong because speed isn't constant as time increases. return to top
Answer 2
B and D
CORRECT
B is correct because distance increases at an increasing rate as time increases, and D is correct because objects begin with a vi of 0, and pick up speed as they fall. It's like the difference when a person falls 3 feet as opposed to 300 feet. The second fall would kill her because her speed would pick up, making her fall with a greater impact. return to top
Answer 3
A and D
INCORRECT
A is not the correct relationship A is wrong because for a falling object, distance increases at an increasing rate. return to top
Answer 4
B and C
INCORRECT
C is wrong because for a free falling object speed isn't constant as time increases. return to top
What's this question really asking?
What's the relationships between speed and time and distance and time ragarding freely falling objects. return to top
