A particle decelerates uniformly from a speed of 30 cm/s to rest in a time interval of 5.0 s.It then has a uniform acceleration of 10 cm/s² for another 5.0 s.The particle moves in the same direction along a straight line.The average speed over the whole time interval is A)20 cm/s B)35 cm/s C)38 cm/s D)100 cm/s E)12 cm/s

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Quizplus · Accepted Answer

The particle first decelerates from 30 cm/s to 0 cm/s in 5 seconds, covering a distance of (1/2)*30*5 = 75 cm. Then it accelerates at 10 cm/s² for 5 seconds, reaching a final speed of 50 cm/s and covering a distance of (1/2)*10*5² = 125 cm. The total distance is 75 + 125 = 200 cm over a total time of 10 seconds, giving an average speed of 200/10 = 20 cm/s.

A Particle Decelerates Uniformly from a Speed of 30 Cm/s