Answer:
False
Explanation:
Convection currents do not produce heat. In fact, convection current are a method of transfer of heat, not of production. Convection occurs when there is a fluid which is heated from bottom, from an external source of heat (such as a pot of boiling water over a flame): the bottom part of the fluid becomes warmer, and so less dense than the colder part, therefore it starts moving up, and it is replaced by the colder parts of the fluid, which go down. Later, these colder parts become warmer, so they start going up, being replaced by new colder parts, etc... in a cycle. This is known as convection current, but it requires an external source of heat, it does not produce heat by itself.
Answer:
100% efficiency
Explanation:
the machine has _100%_ efficiency.
(fill in the blank)
Answer:
1 my brother say that
Explanation:
i know my brother said it
Answer:
<em>1.228 x </em>
<em> mm </em>
<em></em>
Explanation:
diameter of aluminium bar D = 40 mm
diameter of hole d = 30 mm
compressive Load F = 180 kN = 180 x 
N
modulus of elasticity E = 85 GN/m^2 = 85 x 
Pa
length of bar L = 600 mm
length of hole = 100 mm
true length of bar = 600 - 100 = 500 mm
area of the bar A = 
= 
= 1256.8 mm^2
area of hole a = 
= 
= 549.85 mm^2
Total contraction of the bar = 
total contraction = 
==> 
= <em>1.228 x </em><em> mm </em>
Structural constraint is the answer :)
