semiconductors ... silicon, germanium etc ...
Answer:
Part(a): The value of the spring constant is
.
Part(b): The work done by the variable force that stretches the collagen is
.
Explanation:
Part(a):
If '
' be the force constant and if due the application of a force '
' on the collagen '
' be it's increase in length, then from Hook's law

Also, Young's modulus of a material is given by

where '
' is the area of the material and '
' is the length.
Comparing equation (
) and (
) we can write

Here, we have to consider only the circular surface of the collagen as force is applied only perpendicular to this surface.
Substituting the given values in equation (
), we have

Part(b):
We know the amount of work done (
) on the collagen is stored as a potential energy (
) within it. Now, the amount of work done by the variable force that stretches the collagen can be written as

Substituting all the values, we can write

Answer:
45 W
Explanation:
First of all, we need to find the work done by the person to lift the bag. The work done is given by

where
F = 75.0 N is the force applied
d = 1.50 m is the displacement of the bag
Substituting numbers into the formula,

Now we can find the power used, which is given by

where
t = 2.50 s is the time taken
Again, using W=112.5 J, we find

Answer:
The magnitude of magnetic field decreases in comparison to previous case.
Explanation:
Let current flowing in two conductors are
and 
Magnetic field in wire,
Magnetic field due to current I1

Magnetic field due to current I2

When two parallel conductors are carrying currents in the same direction then the magnetic field will be added.

When the direction of one of the current is reversed then the magnitude of the magnetic field midway between them


Hence, the magnitude of magnetic field decreases in comparison to previous case.