course Phy 231
If an object increases velocity at a uniform rate from 5 m/s to 21 m/s in 12 seconds, what is its acceleration and how far does it travel?Answer: acceleration = dv/dt = (21m/sec – 5m/sec)/(12sec) = 1.33 m/sec/sec. ave vel = (21m/s+5m/s)/2 = 13m/s, distance traveled = 13m/s * 12s = 156m.
Sketch a velocity vs. clock time graph for an object whose initial velocity is 5 m/s and whose velocity 12 seconds later is 21 m/s. Explain what the slope of the graph means and why, and also what the area means and why.
Answer: The slope of the graph is the acceleration of the object. The slope is the change in velocity over the change in clock time which is also the definition of acceleration. The area is the distance traveled by the object. It is essentially the average velocity * the time interval.
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