The terms 'variable', 'fixed', 'semi-variable', and 'semi-fixed' have been traditionally used in the cost accounting and mangement acounting literature to describe how a cost reacts to change in activity. Define the above mentioned terms and describe the terms based on a car manufacturer introducing a new engine.

I know how to explain the terms(the first part of the question) but i am not to clear of the second part(the part which is in bold).

Those who know please help.

Thanks in advance.