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## When a bullet is fired from a gun, what is true about the momentum? The gun has more momentum than the bullet, so the momentum is not conserved. The bullet and gun have equal momenta in opposite directions, so the system’s momentum is conserved. The bullet has more momentum than the gun, so the momentum is not conserved. The bullet and the gun have equal momenta in the same direction, so the system’s momentum is conserved.

These are 3 questions and 3 answers.

Question 1.

Explanation:

a) Data:

i) Type of circuit: series

ii) R₁ = 100 Ω

ii) R₂ = 100 Ω

iii) V = 2 V

iv) I = ?

b) Formulas

i) Equivalent resistance, R = R₁ + R₂

ii) Ohm’s law, V = IR

c) Solution

i) R = 100Ω + 100Ω = 200Ω

ii) I = V / R = 2 V / 200Ω = 0.01 A

Question 2)

Explanation:

The nuclear model of the atom states that the atom is neutral, and consists of a nucleus, which holds the protons and the neutrons, and the electrons which are around the nucleous (in regions called orbintals).

The electrons are negatively charged and the protons are positively charged.

The magnitudes of the charges of both electrons and protons are equal.

Therefore, for the atom be neutral, the neutrons cannot have charge.

Question 3.

Explanation:

1) The most basic electrical circuit consists of a 1) potential difference (voltage) source, which gives the “impulse” to the charge to flow, 2) the wire, which is the medium through which the charge flows), and 3) a resistor.

The resistor is the element with “resistance” to the flow of charge, this is it resists or oppose the flow of charge.

Some components, like motors, filaments, buzzers, which content or are resistors per se, transform the current (flow of charge) in other useful forms of energy (motion, light, heat, sound).

The resistor meets Ohm’s law which states R = V / I, at constant temperature.

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## Cecil writes the equation for the reaction of hydrogen and oxygen below. H2 + O2 → H2O Why does his teacher ask him to balance the equation by including the correct coefficients? A.to show that most molecules exist in pairs B.to show that most compounds exist in pairs C.to show that atoms are conserved in chemical reactions D,to show that atoms are created in chemical reactions

Explanation:

Lewis dot structures are the structures which represent the valance electrons of an element forming a compound. The electrons are represented as the dots.

In a compound, the bonded electrons are represented as a bond and lone pair of electrons are represented as dots.

In compound,

Electronic configuration of Nitrogen: Valence electrons in nitrogen = 5

Electronic configuration of hydrogen: Valence electrons in hydrogen = 1

In the given compound, bond pairs are 2 which means number of electrons bonded are 4.

Unbonded electrons left on nitrogen will be 3 and this compound has an extra electron because of the negative charge present on the compound. Hence, total unbonded electrons present on this compound will be 4.

Therefore, the lewis dot structure will be Option D.