A dragster crosses the finish line at 140 m/s, having accelerated at a constant rate the whole way from rest. What was its average velocity for the run?
A35 m/s
B70 m/s
C105 m/s
D140 m/s
Answer & Solution
Correct answer: B. 70 m/s
1. For constant acceleration, average velocity is the mean of the initial and final velocities.
2. v_avg = (v_0 + v_f) / 2 = (0 + 140 m/s) / 2.
3. v_avg = 70 m/s.
_Source: OpenStax Physics (CC BY 4.0), Ch 3 "Acceleration", section 3.2 Representing Acceleration with Equations and Graphs_
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