A size D flashlight battery will deliver 1.2 A-h (amp-hour) at 1.5V. An automobile battery will deliver 55 A-h at 12V. the flashlight battery is cylindrical with a diameter of 3.3 cm, a length of 5.6 cm, and a mass of .086kg. The automobile battery is rectangular with dimensions 30cm by17cm by 23cm and a mass of 23kg.
a.) what is the available electric energy in Joules in each battery?
b.) what is the amount of energy stored per cubic centimeter by each battery?
c.) what is the energy stored per kg of each battery?
a.) what is the available electric energy in Joules in each battery?
b.) what is the amount of energy stored per cubic centimeter by each battery?
c.) what is the energy stored per kg of each battery?
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a) Energy = power*time
1.2 A-h = 1.2*3600 A-s. Energy = 1.5*1.2*3600 J = 6.48 kJ for D cell Answer
55 A-h = 55*3600 A-s. Energy = 12*55*3600 J = 2.376 MJ for automobile battery. Answer
b) Volume of D cell = pir^2h
= pi*1.65^2*5.6
= 47.897 cm^3
so energy/cm^3 = 6.48*10^3/47.89 = 135.39 J/cm^3 Answer
Volume of automobile battery = 30*17*23 = 11730 cm^3
so energy/cm^3 = 2.376*10^6/11.730*10^3 = 0.202*10^3 J/cm^3 = 202.55 J/cm^3 Answer
c) weight of D cell = 0.086 kg.
So energy/kg = 6.48*10^3/0.086 = 75.349 kJ/kg Answer
weight of automobile battery = 23 kg
Energy/kg = 2.376*10^6/23 = 0.1033 MJ/kg = 103.3 kJ/kg Answer
1.2 A-h = 1.2*3600 A-s. Energy = 1.5*1.2*3600 J = 6.48 kJ for D cell Answer
55 A-h = 55*3600 A-s. Energy = 12*55*3600 J = 2.376 MJ for automobile battery. Answer
b) Volume of D cell = pir^2h
= pi*1.65^2*5.6
= 47.897 cm^3
so energy/cm^3 = 6.48*10^3/47.89 = 135.39 J/cm^3 Answer
Volume of automobile battery = 30*17*23 = 11730 cm^3
so energy/cm^3 = 2.376*10^6/11.730*10^3 = 0.202*10^3 J/cm^3 = 202.55 J/cm^3 Answer
c) weight of D cell = 0.086 kg.
So energy/kg = 6.48*10^3/0.086 = 75.349 kJ/kg Answer
weight of automobile battery = 23 kg
Energy/kg = 2.376*10^6/23 = 0.1033 MJ/kg = 103.3 kJ/kg Answer