Answer:
<em>0.45 mm</em>
Explanation:
The complete question is
a certain fuse "blows" if the current in it exceeds 1.0 A, at which instant the fuse melts with a current density of 620 A/ cm^2. What is the diameter of the wire in the fuse?
A) 0.45 mm
B) 0.63 mm
C.) 0.68 mm
D) 0.91 mm
Current in the fuse is 1.0 A
Current density of the fuse when it melts is 620 A/cm^2
Area of the wire in the fuse = I/ρ
Where I is the current through the fuse
ρ is the current density of the fuse
Area = 1/620 = 1.613 x 10^-3 cm^2
We know that 10000 cm^2 = 1 m^2, therefore,
1.613 x 10^-3 cm^2 = 1.613 x 10^-7 m^2
Recall that this area of this wire is gotten as
A = 
where d is the diameter of the wire
1.613 x 10^-7 = 
6.448 x 10^-7 = 3.142 x 
=
d = 4.5 x 10^-4 m = <em>0.45 mm</em>
<span>1. Frictional force</span>
A naturally occurring force related
to two bodies in motion is frictional force. Friction is a type of force which
includes two bodies resisting each other –either motion of solid surfaces,
fluid layers, material elements and compounds gliding against each other. They
key point of this frictional force is that the two forces are in the opposite point
of direction with each other. For example, when you are cold, as you rub your
hands together notice that when your right hand is going upward, your left hand
is downward and thus creates heat. That is one type of friction force outcome,
the heat.
Answer: B
White paper reflects some of the incoming waves,
while black absorbs all of the incoming waves.
Explanation:
Light is reflected off of white surfaces. Light is absorbed by opaque materials and transmitted through transparent objects.
In the case of a white paper, a white paper can be considered as a translucent material in which some of the light incident on it bounces off while some pass through it. Therefore, we can conclude that White paper reflects some of the incoming waves,
while black absorbs all of the incoming waves.
Answer:
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Featured snippet from the web
The elevators which are on the tail section are used to control the pitch of the plane. A pilot uses a control wheel to raise and lower the elevators, by moving it forward to back ward. Lowering the elevators makes the plane nose go down and allows the plane to go down.
Explanation:
If two forces act on an object in the same direction, the net force is equal to the sum of the two forces
