Answer:1.84
Explanation:
Given
Humming bird travels 1.2 m along a straight line at height of 3.4 m
Now bird drops 1.4 m to hover in front of the flower
So bird net displacement is
displacement
displacement
=1.84
Answer:
The part that completes the nuclear equation is:

Explanation:
<h2>A) Preliminar explanation</h2>
The <em>nuclear equation</em> represents a nuclear reaction: the change of the nucleus of an atom.
The given equation represents an actinium atom releasing an alpha particle.
This is the meaning of each part of the equation:
- Ac is the chemical symbol of actinium
- The superscript to the left of the chemical symbol is the mass number of the atom (number of protons plus number of neutrons). The mass number is 225.
- The subscript to the left of the chemical symbol is the atomic number of the atom (number of protons). The atomic number is 89.
is the symbol of the alpha particle. It is an atom of helium- The mass number is 4
- The atomic number is 2
<h2>B) Solution</h2>
To <em>complete the nuclear equation </em>you must do two balances: mass number balance and atomic number balance.
<u>i) Mass number balance</u>
- 225 = A + 4 ⇒ A = 225 - 4 = 221
<u>ii) Atomic number balance</u>
- 89 = Z + 2 ⇒ Z = 89 - 2 = 87
Therefore, the mass number of the unknown atom is 221, and the atomic number is 87.
From a periodic table, the element with atomic number 87 is francium, Fr.
Now, you have the chemical symbol, the atomic number, and the mass number of the unknown atom, which lets you to write the atom that completes the <em>nuclear equation</em>.

Answer:
The current in a resistor decreases by a factor of 4.
Explanation:
I = 
Where (I) is the current, (E) is the voltage and (R) is the resistance.
Decreasing the voltage by 4 gives;
I = 0.25
Since you have multiplied
by 0.25,
You have to multiply I by 0.25 so the current decreases by a factor of 4.
To solve this problem it is necessary to apply the concepts related to pressure as a unit that measures the force applied in a specific area as well as pressure as a measurement of the density of the liquid to which it is subjected, its depth and the respective gravity.
The two definitions of pressure can be enclosed under the following equations

Where
F= Force
A = Area

Where,
Density
g = Gravity
h = Height
Our values are given as,


If we make a comparison between the lid and the tube, the diameter of the tube becomes negligible.
Matching the two previous expressions we have to

Re-arrange to find h




Therefore the height of water in the tube is 7.9cm