Quiz 1: How much energy is
contained in 1 liter of gasoline? Find out approximately by using data you know about your car. |
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Consider what you know about your car or some average car: Mileage (let's say 10 km/l), how far you get on this (500 km), engine power (100 kW), engine efficiency (??? - think) how long it takes you to go the 500 km and how much percent of the engine power you use for this on average (you are not always going full throttle!). | ||
Energy, by the way, is power times time. | ||
Quiz 2: How large or small are 10 kWh /l - in comparison to known energy (densities). | ||
How far up do you have to drag you body to gain 10 kWh? Potential energy, by the way, is E_{pot} = mgh. | ||
You store energy by pulling up a ball of lead in your (now unused) chimney (diameter = 20 cm). How far up do you have to pull it to store the 10 kWh? (Specific density of lead = 11,4 g/cm^{3}). | ||
How much water can you bring from 10 ^{o}C to a boil? The specific heat capacity of water is 4.2 kJ/kgK. A Joule J, as we know, is equal to 1 Nm or 1 Ws | ||
Your power output on a bicycle for some length of time is ??? kW. Mine is at best » 100 W. How far and / or how long do you have to ride you bike before you used up 10 kWh? How many Big Mac's have you worked off then (a Big Mac of about 120 g contains 2071,74 kJ = 494,94 kcal. | ||
How much energy do you convert into heat if you wrap your car
around a tree at 100 km/h. In other words: 1/2mv^{2} =
??? KWh (without the gasoline burning). Your car weighs about |
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How fast do you need to hit the tree so that the kinetic energy contained in 50 l » 50 kg of gasoline equal the kinetic energy? | ||
Quiz 3: This and That | ||
Why do you have plenty of room in an electric car for the battery? | ||
Why do you want you batteries not to be extremely light weight in a submarine? | ||
Why is the current collector in a powerful battery not to be sneered at? Hint: Your electric car has a 100 kW motor; a battery cell has a voltage of about 3 V. | ||
You want to be able to run your 100 kW electric motor car for 5 hours at half the capacity? What is the required battery size? How long does it take you to recharge that battery from your standard outlet (230 V AC; 16 A)? | ||
Take a 1 kWh Li ion battery with a voltage of 3V. How much charge Q must be stored in it when it is fully loaded? | ||
How much Li atoms would that be? What is their weight? Compare to the energy density figure and discuss. | ||
Solutions are found in the Li Ion Battery module |
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© H. Föll (Electronic Materials - Script)