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3 years ago

Which of the following has zero acceleration?

2 answers:

5 0

'Acceleration' means any change in speed or direction
of motion.

so
C). No acceleration. Straight, at constant speed.
No change of speed or direction.

anyanavicka [17]3 years ago

3 0

Answer:

C. A person running 100 m straight across a field at a constant speed.

Explanation:

Acceleration is defined as the change in the velocity per unit time. Velocity have both direction and magnitude (speed) . So, acceleration involves both change in direction and speed.

A). The satellite is in a curved orbit, so direction of satellite is constantly changing. Hence, not the answer.

B). The car is following a curve, so its direction is changing. Hence, not the answer.

C). The person is running straight at constant speed which means no change of speed or direction. Hence, it is the answer.

D). The person is on curved track, so his/her direction is changing. Hence, not the answer.

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A substance has a high melting point and conducts electricity in the liquid phase The is substance is

posledela

Answer:

oxygen

Explanation:

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3 years ago

3 ways to use electric current

pochemuha

A outlet,electrical,batteries

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3 years ago

Determine which of the following pairs of reactants will result in a spontaneous reaction at 25°C. None of the above pairs will

Alla [95]

Answer:

Only $Fe^{3+}+Mg$ gives spontaneous reaction.

Explanation:

A redox reaction will be spontaneous if standard reduction potential ( $E^{0}$ ) of the reaction is positive. Because it leads to negative standard gibbs free energy change ( $\Delta G^{0}$ ), which is a thermodynamic condition for spontaneity of a reaction.

$E^{0}=E^{0}(reduction)-E^{0}(oxidation)$

Where $E^{0}(reduction)$ and $E^{0}(oxidation)$ represents standard reduction potential of reduction half cell and standard reduction potential of oxidation half cell.

(1) Oxidation: $Mg-2e^{-}\rightarrow Mg^{2+}$ ; $E_{Mg^{2+}\mid Mg}^{0}=-2.38V$

Reduction: $Fe^{3+}+3e^{-}\rightarrow Fe$ ; $E_{Fe^{3+}\mid Fe}^{0}=-0.04V$

So, $E^{0}=E_{Fe^{3+}\mid Fe}^{0}-E_{Mg^{2+}\mid Mg}^{0}=(-0.04+2.38)V=2.34V$

Hence this pair will give spontaneous reaction.

(2) Similarly as above, $E^{0}=E_{Pb^{2+}\mid Pb}^{0}-E_{Au^{+}\mid Au}^{0}=(-0.13-1.69)V=-1.82 V$

Hence this pair will give non-spontaneous reaction.

(3) Similarly as above, $E^{0}=E_{Ag^{+}\mid Ag}^{0}-E_{Br_{2}\mid Br^{-}}^{0}=(0.80-1.07)V=-0.27 V$

Hence this pair will give non-spontaneous reaction.

(4) Similarly as above, $E^{0}=E_{Li^{+}\mid Li}^{0}-E_{Cr^{3+}\mid Cr}^{0}=(-3.04+0.74)V=-2.30 V$

Hence this pair will give non-spontaneous reaction.

6 0

2 years ago

Compared to the charge of a proton, the charge of all electron has

Kay [80]

Answer: option (4) the same magnitude and the opposite sign.

Justification:

1) Electrons are negative particles thar are around the nucleus of the atom (in regions called orbitals).


2) Protons are positive particles that are inside the nuclus of the atom.


3) The nucleus of the atom has the same number of protons as electrons are in the orbitals of the atom.


4) The atoms are neutral (neither positive nor negative) because there are the same number of electrons and protons and their charge are of the same magnitude but different sign: (+) + (-) = 0: positive + negative = neutral.

6 0

2 years ago

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Which of earths spheres contains most of its mass?

zysi [14]

The geosphere is about 99.94% of Earth's mass, so C is the answer.

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3 years ago

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