A driver wishes to buy a new car. The table below gives some data about an electric car and one with a petrol engine.
Electric car
Petrol engine car
Cost (£)
27 000
15 000
Running cost per year (£)
250
2 000
Average lifetime (years)
12
12
Which car would be the most economic over its 12 year lifetime?
Use data from the table above to support your answer.
You should include the difference in cost in your answer.

Asquare isothermal chip is of width w=5 mm on a side and is mounted in a substrate such that its side and back surfaces are well insulated; the front surface is exposed to the flow of a coolant at tinf=15 °c. from reliability considerations, the chip temperature must not exceed t=85 °c. if the coolant is air and the corresponding convection coefficient is h=200 w/m2 x k, what is the maximum allowable "power" of the chip? if the coolant is a liquid for which h=3000 w/m2 x k, what is the maximum allowable power of the chip?