A lightweight electric car is powered by sixteen 12-V batteries. At a speed of 6

Question

A lightweight electric car is powered by sixteen 12-V batteries. At a speed of 60 km/h, the average frictional force is 900 N. What must be the power of the electric motor if the car is to travel at a speed of 60 km/h?

ANS: 1.5E4 W

If each battery can deliver a total charge of 150 Ah before recharging, what is the total charge in coulombs that can be delivered by the sixteen batteries before recharging?

ANS: 8.64E6 C

What is the total electric energy delivered by the sixteen batteries before recharging?

ANS: 1.04E8 J

How far can the car travel at 60 km/h before the batteries must be recharged?

ANS: 115 km

What is the cost per kilometer if the cost of recharging the batteries is 9.30 cents per kilowatt-hour?

This is where my issue is, please help

Explanation / Answer

work or energy is force * distance.

to change to power, divide that by time

60 km/hour = 16.67 m/s

so power required to drive 16.67 m/s is

P = 900 * 16.67 meter / 1 sec = 15 kW

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150 amp-hr*16 = 2400 amp-hour

or 2400 (C/s) * 3600 s = 8.64 MC

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150 amp-hr*16 = 2400 amp-hour

2400 amp-hour * 12v = 28800 watt-hour

28800 watt-hour * 3600 sec/hour = 103.68 MJ = 1.04*10^8 J

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28.8 kwatt-hour / 15 kW = 1.92 hour

1.92 hour * 60 km/hr = 115.2 km = 115 km

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28.8 kwatt-hour * 9.3 cents / kWh = 267.84 cents

267.84/115.2 = 2.32 cents/km

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