In the context of a roof, why is extra flashing useful in a valley? Valleys structurally weaken a roof.
There is no underlayment in a valley.
Precipitation tends to run into valleys.
There are no shingles in a valley.

The temperature of air decreases as it is compressed by an adiabatic compressor. a)- true b)- false

Aturning operation is performed with following conditions: rake angle of 12°, a feed of 0.35 mm/rev, and a depth of cut of 1.1 mm. the work piece is aluminum alloy 6061 with t6 heat treatment (a16061-t6). the resultant chip thickness was measured to be 1.0 mm. estimate the cutting force, fc. use shear stress of 207 mpa and coefficient of friction on the tool face of 0.6.

Modern high speed trains do not have perpendicular expansion gaps where rails are joined end-to-end any more they are mostly welded together but what might happen if there was a spell of particularly hot weather that causes inspection of the tracks?