Power:

$\overline{){\mathbf{P}}{\mathbf{=}}{\mathbf{i}}{\mathbf{V}}}$

$\overline{){\mathbf{P}}{\mathbf{=}}\frac{\mathbf{W}}{\mathbf{t}}}$

Work done:

$\overline{){\mathbf{W}}{\mathbf{=}}{\mathbf{\u2206}}{\mathbf{K}}{\mathbf{E}}}$

A light-rail commuter train draws 620 A of 700 V DC electricity when accelerating.

a) What is its power consumption rate in kilowatts?

b)How long does it take (in seconds) to reach 19.0 m/s starting from rest if its loaded mass is 5.30 ✕ 10^{4} kg, assuming 95.0% efficiency and constant power?

c) Find its average acceleration. (Enter the magnitude in m/s^{2}.)

d) Discuss how the acceleration you found for the light-rail train compares to what might be typical for an automobile.

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