Starting from rest,a car accelerates down a straight road with constant acceleration a₁ for a time t₁,then the acceleration is changed to a different constant value a₂ for an additional time t₂.The total elapsed time is t₁ + t₂.Can the equations of kinematics be used to find the total distance traveled? A)No,because this is not a case of constant acceleration. B)Yes,use (a₁ + a₂)/2 as the average acceleration and the total time in the calculation. C)Yes,use a₁ + a₂ as the acceleration and the average time (t₁ + t₂)/2 in the calculation. D)Yes,break the problem up into 2 problems,one with the conditions for the first time interval and the other with the conditions for the second time interval,noting that for the second time interval the initial velocity is that from the end of the first time interval.When done,add the distances from each of the time intervals.

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Quizplus · Accepted Answer

Since the acceleration changes, we cannot use the equations of kinematics with constant acceleration for the entire motion. Therefore, we need to break the problem up into two separate intervals, one with the initial acceleration and the other with the final acceleration. We can use the equations of kinematics with constant acceleration for each interval separately. We must also note that the initial velocity for the second interval is the final velocity from the first interval. Finally, we add the distances from each interval to find the total distance traveled.

Starting from Rest,a Car Accelerates Down a Straight Road with Constant