The diameter of a circle is m and an equilateral triangle is inscribed inside. The formula for calculating the area of an equilateral triangle

Because it is an inscribed regular triangle, the center of the circle must be on the 3-line, so r * ctg30 = 1 / 2 side length and side length = 2R * ctg30
Formula: side length = 2R * ctg30

Area formula of regular triangle
Given the perimeter of an equilateral triangle as a, find the area of the equilateral triangle
Just write the formula!

1 / 2 (A / 3) ^ 2 * radical 3 / 2
=The root of 12 is three times a square

Calculate the area of a triangle with unequal sides
The length of the three sides is 13.3 meters, 60.60 meters, and 62 meters to calculate the triangle area

Using Helen's formula:
Suppose that the lengths of the three sides are a, B, C
p=(a+b+c)/2
Then the square of the area s ^ 2 = P * (P-A) * (P-B) * (P-C)

How to calculate the area of unequal triangle

Helen formula s = √ [P (P-A) (P-B) (P-C)]
p=(a+b+c)/2

Is there induced electromotive force when a section of wire cuts in magnetic field?
A section of unclosed wire is cut in a magnetic field. Is there induced current in the motion of magnetic induction line?

If there is no current in the conductor, it will not be affected by the magnetic force. For example, if the conductor is not a part of the closed circuit, it will produce the induced electromotive force, but the magnetic force in the conductor will not be affected

Why the induced electromotive force will be produced when the wire is cut in a uniform magnetic field
There is no change in the magnetic flux of a wire, but the condition of generating the induced electromotive force is the change in the magnetic flux. I want to know how the magnetic flux of a wire changes;

You're not right. The condition of producing induced current is the change of magnetic flux. The electrons in the wire will also move because of the motion of the wire. The electrons move in the magnetic field and move towards one end of the wire by Lorentz force, so that the two ends of the wire are charged with different kinds of charges. In this way, the electromotive force is generated at both ends of the wire
You can take an electron in the wire, analyze its force and motion, and you will know all about it

A conducting bar cuts the magnetic field at a sinusoidal speed
If it is used as the voltage of the primary coil of the transformer, should the resistance of the conductor bar be considered when calculating the voltage of the resistance R of the secondary coil? If not, why? How to distribute the voltage? If the resistance R is in the secondary coil, can the voltage of the primary coil be distributed according to the resistance value?

To be precise, it should be considered. The resistance of the conductor bar converted to the secondary coil is equivalent to a resistance whose resistance value is the square of the number of turns, which is connected in series with the resistance of the secondary coil. The converted resistance is close to the resistance of the secondary coil

When a straight wire cuts the magnetic induction line in the magnetic field, must there be induced voltage in the wire or at both ends of the wire

When a straight wire cuts the magnetic induction line in the magnetic field, there must be induced voltage at both ends of the wire
Because the essence is the cutting of current element, the wire can be regarded as a large current element, and the charge will be distributed to both ends to form a potential difference, namely voltage

If a section of conductor moves in a magnetic field to cut a magnetic induction line, then
When a section of conductor moves in a magnetic field, then ()
A. There must be an induced current in a conductor
B. There are both induced current and induced voltage in conductor
C. There may be induced voltage at both ends of the conductor
D. There must be an induced voltage at both ends of a conductor

D. Induction voltage does not necessarily have induction current, only closed circuit can have induction current

A straight conductor with length of L = 10 cm, perpendicular to the magnetic induction line, is put into a uniform magnetic field. When I = 2A current is applied in the conductor, the ampere force received by the conductor is large
Put a straight conductor with length of L = 10 cm perpendicular to the magnetic induction line into a uniform magnetic field. When the current of I = 2A is applied to the conductor, the ampere force received by the conductor is 1 times the 7th power n of 10, and the magnetic induction intensity B of the magnetic field can be obtained

F=BIL
B=F/(IL)=10^-7/(2*0.1)T=5*10^-7T

The diameter of a circle is m and an equilateral triangle is inscribed inside. The formula for calculating the area of an equilateral triangle