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Multiple Choice
The position function of a particle is given by . At what time is the speed of the particle minimum?
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Verified step by step guidance
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Step 1: Understand that the speed of the particle is the absolute value of its velocity. Velocity is the derivative of the position function s(t). Begin by finding the derivative of s(t), which is v(t) = ds/dt = 3t^2 - 12t + 9.
Step 2: To find when the speed is minimum, first identify the critical points of the velocity function v(t). Set v(t) = 0 and solve for t: 3t^2 - 12t + 9 = 0.
Step 3: Factorize the quadratic equation 3t^2 - 12t + 9 = 0. This simplifies to 3(t - 1)(t - 3) = 0, giving t = 1 and t = 3 as critical points.
Step 4: Evaluate the speed (absolute value of velocity) at the critical points t = 1 and t = 3, as well as at the endpoints of the given interval (if applicable). Compare these values to determine where the speed is minimum.
Step 5: Confirm the result by analyzing the behavior of the velocity function v(t) and its absolute value |v(t)| around the critical points. This ensures the minimum speed is correctly identified.