pm1

Mar 21, 2012
323
8
Status
Pre-Medical
The passage talks about an accelerating car and refers to lift.

As a vehicle accelerates, the difference in air speed (and consequently air pressure) above and below it generates the upward force of lift, which reduces contact between the tires of the car and the surface of the road, which in turn reduces friction.
29. Which of the following statements BEST describes how lift occurs with an accelerating car?

A. Increased laminar airflow above the car, plus increased turbulent airflow below the car, reduces air pressure above the car while increasing air pressure below the car, creating lift
B. Increased laminar airflow above the car, plus increased laminar airflow below the car, equally reduces air pressure above and below the car, creating lift
C. Decreased laminar airflow above the car, plus decreased turbulent airflow below the car, increases air pressure above the car while reducing air pressure below the car, creating lift
D. Decreased laminar airflow above the car, plus increased turbulent airflow below the car, increases air pressure above the car while reducing air pressure below the car, creating lift

Answer: A

I get it how the pressure needs to be higher below the car in order to induce lift. However, shouldn't there be a difference in air speed? Shouldn't the answer choice say "increased laminar airflow above the car, plus decreased turbulent airflow.."

Any help/comment highly appreciated! :)
Thank you!