Physics Review Question Unit: mechanics Year: 1997 Question#: 6 Question: The displacement-time graph below represents the motion of a cart along a straight line. During which interval was the cart accelerating? (1 ) AB (2 ) BC (3 ) CD (4 ) DE What is this question really asking? Explanation by: Diana L. [ Return to question menu ] Answer 1 AB CORRECT During the interval AB, the slope is positive, but isn't a constant velocity. The displacement rapidly increases with an increasing slope within a small amount of time. The cart is, thus, accelerating. return to top Answer 2 BC INCORRECT During the interval BC, the slope is positive, but at a constant velocity. The cart is moving uniformly and not accelerating. return to top Answer 3 CD INCORRECT During the interval CD, displacement stays at a constant while the time increases. Therefore the cart is not moving during this time. It is definitely not accelerating. return to top Answer 4 DE INCORRECT During the interval DE, velocity is a constant. return to top What's this question really asking? At which interval is the velocity not a constant? (Keep in mind that the slope of a displacement vs. time graph represents the velocity) You are looking for a region where the velocity is changing. return to top |
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