explain how many minimum number of geostationary satellites are required for global coverage of T.V transmission
1 answer:
You might be interested in
The magnitude of the frictional force is B) 300 N
Explanation:
For this problem, we just have to consider the forces acting on the box in the horizontal direction.
There are only two forces in this direction:
- The pull applied by the man, of magnitude F=300 N, forward
- The frictional force, , acting backward
So the equation of motion for the box is
where
m is the mass of the box
a is its acceleration
However, the box is at rest, so its acceleration is zero:
a = 0
This means therefore that
And so the magnitude of the frictional force is equal to the pulling force:
Learn more about friction:
#LearnwithBrainly
1) 3.0 m
2) 2.40 m
Explanation:
1)
A concave mirror is a reflecting surface that causes the reflection of the rays of light coming to the mirror, producing an image of the object facing the mirror.
There are two types of mirror:
- Concave mirror: this is curved inward - as a result, the rays of light coming from the object are reflected back into a single point, called focal point
- Convex mirror: this is curved outward - as a result, the rays of light coming from the object are reflected back into diverging direction, not into a single point
For a curved mirror, the radius of curvature is twice the focal length:
Where
R is the radius of curvature
f is the focal length
In this problem,
f = 1.50 m
So, the radius of curvature is
2)
The distance of the image from the mirror can be found by using the mirror equation:
where
f is the focal length
p is the distance of the object from the mirror
q is the distance of the image from the mirror
IN this problem we have:
f = 1.50 m is the focal length
p = 4.00 m is the distance of the object from the mirror
Solving for q, we find:
(a) 12.0 V
In this problem, the capacitor is connected to the 12.0 V, until it is fully charged. Considering the capacity of the capacitor, , the charged stored on the capacitor at the end of the process is
When the battery is disconnected, the charge on the capacitor remains unchanged. But the capacitance, C, also remains unchanged, since it only depends on the properties of the capacitor (area and distance between the plates), which do not change. Therefore, given the relationship
and since neither Q nor C change, the voltage V remains the same, 12.0 V.
(b) (i) 24.0 V
In this case, the plate separation is doubled. Let's remind the formula for the capacitance of a parallel-plate capacitor:
where:
is the permittivity of free space
is the relative permittivity of the material inside the capacitor
A is the area of the plates
d is the separation between the plates
As we said, in this case the plate separation is doubled: d'=2d. This means that the capacitance is halved: . The new voltage across the plate is given by
and since Q (the charge) does not change (the capacitor is now isolated, so the charge cannot flow anywhere), the new voltage is
So, the new voltage is
(c) (ii) 3.0 V
The area of each plate of the capacitor is given by:
where r is the radius of the plate. In this case, the radius is doubled: r'=2r. Therefore, the new area will be
While the separation between the plate was unchanged (d); so, the new capacitance will be
So, the capacitance has increased by a factor 4; therefore, the new voltage is
which means