what is the physiologicaldifference(i.e. the difference in mechanisms ) between normal and forced experation?

Answer 1

Normal experation is passive (ther isn't any energy used), there is an increase in atmophereic pressure in your lungs and the air moves to the lesser pressure...Like a balloon. It isn't the
Forced experation is when the diaphram as well as the intercostal muscle contract to help push the air out for your lungs quickly...such as when you squeeze a balloon to release the air quickly.