The main reason for making the cover of a vacuum
flask airtight is to prevent heat loss by
A. conduction
B. evaporation
C. radiation
D. convection

15. one purpose of the tread pattern on a tire is to a reduce tire wear. b. reduce traction c. allow water to flow away from the tire. d. look impressive.

What is the stall speed at sea level of an airplane that weights 10000 lbs., has a wing area of 300ft^2, and a maximum lift coefficient of 1.4? what is the stall speed if flaps that double cl,max are applied?

You are given two vectors a⃗ =−3.00ι^ 5.00j^ and b⃗ =5.00ι^ 2.00j^. let the counterclockwise angles be positive.