Fiberglass insulation trap layers of air to prevent heat loss due to all but one that is

the answer is C. evaporation

wire in brush may conduct electricity from cell to drill and vice versa electrc shock possible

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2