Answer:
a) the two-way concrete joist framing system
Explanation:
A waffle slab is also known as ribbed slab, it is a slab which as waffle like appearance with holes beneath. It is adopted in construction projects that has long length, length more than 12m. The waffle slab is rigid, therefore it is used in building that needs minimal vibration.
Answer:
as all the people should go near stratosphere
Given:
diameter of sphere, d = 6 inches
radius of sphere, r =
= 3 inches
density,
= 493 lbm/ 
S.G = 1.0027
g = 9.8 m/
= 386.22 inch/ 
Solution:
Using the formula for terminal velocity,
=
(1)

where,
V = volume of sphere
= drag coefficient
Now,
Surface area of sphere, A = 
Volume of sphere, V = 
Using the above formulae in eqn (1):
= 
=
= 
Therefore, terminal velcity is given by:
=
inch/sec