Answer 1:
Like most electrical mechanical devices, electric motors have mechanical bearings that eventually wear out.
The graphite brushes and commutator of older DC motors can also wear out over time
Answer2:
Question two is not specific enough!!
Are we talking DC?? Because if so, then yes, nothing will happen. Assuming you are insulted by ground.
Ac is a different story, as the two would light up dangerously and etc.
-your welcome!!
Answer:
Explanation:
Given
scale i.e. 
Using Reynolds number similarity


Properties of air

Properties of sea water





Answer: Something that has air molecules.
Explanation:
Answer:
(a) See attachment
(b) The two planes are parallel because the intercepts for plane [220] are X = 0,5 and Y = 0,5 and for plane [110] are X = 1 and Y = 1. When the planes are drawn, they keep the same slope in a 2D plane.
(c) 
Explanation:
(a) To determine the intercepts for an specific set of Miller indices, the reciprocal intercepts are taken as follows:
For [110]

For [220]

The drawn of the planes is shown in the attachments.
(b) Considering the planes as two sets of 2D straight lines with no intersection to Z axis, then the slope for these two sets are:
For (1,1):

For (0.5, 0.5):

As shown above, the slopes are exactly equal, then, the two straight lines are considered parallel and for instance, the two planes are parallel also.
(c) To calculate the d-spacing between these two planes, the distance is calculated as follows:
The Miller indices are already given in the statement. Then, the distance is:


Answer:
B. The thickness of the heated region near the plate is increasing.
Explanation:
First we know that, a boundary layer is the layer of fluid in the immediate vicinity of a bounding surface where the effects of viscosity are significant. The fluid is often slower due to the effects of viscosity. Advection i.e the transfer of heat by the flow of liquid becomes less since the flow is slower, thereby the local heat transfer coefficient decreases.
From law of conduction, we observe that heat transfer rate will decrease based on a smaller rate of temperature, the thickness therefore increases while the local heat transfer coefficient decreases with distance.