PHYSICS HIGH SCHOOL

A reaction that requires free energy:a. must be endothermic.
b. is nonspontaneous.
c. must correspond to a decrease in entropy.
d. is spontaneous.

Answers

Answer 1
Answer:

A reaction that requires free energy is spontaneous. The answer is letter D. this is because it does not any external energy to apply unto it to make the reaction happen. It just happens by itself that is why it is spontaneous.

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The principal limitation of wind power is unpredictability. Please select the best answer from the choices provideda. True b. False

A resistor in a circuit dissipates energy at a rate of 1 W. If the voltage across the resistor is doubled, what will be the new rate of energy dissipation?

Answers

The new power dissipation will be 4 watts.

A car that is initially moving to the right with a velocity of 4 m/s is pushed by a -5 N force as it moves from 5 meters to 20 meters. How much work is done to the car by this force?

Answers

Answer:

the work done on the car by the applied force is 75 J.

Explanation:

Given;

initial velocity of the car, v = 4 m/s

applied force in opposite direction, F = 5N

initial position of the car, x₀ = 5 m

final position of the car, x₁ = 20 m

displacement of the car, Δx = x₁ - x₀ = 20 m - 5m

                                                            = 15 m

The work done on the car by the applied force is calculated as follows;

W = F.Δx

W = 5 x 15

W = 75 J

Therefore, the work done on the car by the applied force is 75 J.

a. Define Valency. b. Write the symbol and valency of the following : (i) Oxygen (ii) potassium 7. a. Magnesium burns in Oxygen to form Magnesium Oxide. a) Name the reactants b) Name the Products c) Write the word equation for the above reaction.

Answers

⚘ YourAnswers:

A) Valency is the combining capacity of any element. Valence electrons refers to the electrons found in the outermost shell of the atom of the element.

B) Symbol and valency:

  1. Oxygen(O) = (At. no. 8) = -2(Valency)
  2. Potassium(K) = (At. no. = 19) = +1(Valency)

C) The reaction would be:

\large{ \boxed{ \rm{2Mg + O_2 \longrightarrow \: 2MgO}}}

  • Reactants = Magnesium and Oxygen
  • Products = Magnesium oxide
  • Word equation:

\large{ \boxed{ \rm{Magnesium + Oxygen \longrightarrow Magnesium oxide.</p><p>}}}

━━━━━━━━━━━━━━━━━━━━

Answer:

Oxygen-Symbol-O Potassium Symbol-K

The term “radiation” refers to hot materials inside the Earth rising towards Earth’s surface, cooling, and sinking back down.

Answers

No, that's not a true statement.  The process you've detailed
is a perfect description of "convection", not radiation.

a gust of wind blows an apple from a tree. As the apple falls, the gravitational force on the apple is 2.25N downward and the force of the wind on the apple is 1.05N to the right. Find the magnitude and the direction of the net force on the apple.

Answers


Vertical component =  2.25 N downward

Horizontal component = 1.05 N to the right

Magnitude of the net force = √ (2.25² + 1.05²)
                                              = √6.165 =              2.483 N  (rounded)

Direction of the net force = tan⁻¹ (1.05/2.25) to the right of downward

                                           = tan⁻¹ ( 7/15 ) to the right of downward

                                           = 25° to the right of downward (rounded)

The magnitude of the net force on the apple is \boxed{2.48{\text{ N}}}.

The direction of the net force is with vertical \boxed{25^\circ}.

Further explanation:

Here, we have to calculate the magnitude and the direction of the net force on the apple.

Given:

The gravitational force exerted on the apple is 2.25{\text{ N}}.

Force exerted by the wind on the apple is 1.05{\text{ N}}.

Formula and concept used:

The gravitational force is a universal force and it act in downward direction that is towards the center of the earth.

The direction of the force exerted by the wind on the apple is towards write side in the horizontal direction.

So, the angle between the gravitational force and force due to wind will be 90^\circ that is both the forces are perpendicular to each other.

Consider gravitational force is W and force due to wind is F.

So, the net force applied on the apple is,

\boxed{R=\sqrt {\left( {{W^2} + {F^2} + 2WF\cos \theta } \right)} }

Here, \theta is the angle between both the forces which is equal to the 90^\circ.

So, the above equation can be written as,

R=\sqrt {{W^2} + {F^2}}                                                                                   …… (1)

The direction of the net force can be written as,

\boxed{\phi={{\tan }^( - 1)}\left( {(F)/(W)}\right)}                                  ….. (2)

Calculation:

Substitute 2.25{\text{ N}} for W and 1.05{\text{ N}} for F in the equation (1).

\begin{aligned}R&=\sqrt {{{2.25}^2}+{{1.05}^2}}\n&=\sqrt {6.165}\n&=2.48{\text{ N}}\n\end{gathered}

For the direction,

Substitute 2.25{\text{ N}} for W and 1.05{\text{ N}} for F in the equation (2).

\begin{aligned}\phi&={\tan ^( - 1)}\left( {\frac{{1.05}}{{2.25}}} \right)\n&=25^\circ\n\end{aligned}

Thus, the net force on the apple is \boxed{2.48{\text{ N}}} and direction of the net force is with vertical \boxed{25^\circ}.

Learn more:

1. Water is a compound: brainly.com/question/1073452

2. Expansion of the gas with change in temperature: brainly.com/question/9979757

3. Two arrows are fired simultaneously with the speed of 30m/s brainly.com/question/2370982

Answer detail:

Grade: Senior School

Subject: Physics

Chapter: Force

Keywords:

Wind blow, apple falls, gravitational force, wind force, magnitude of force, direction of force, 2.25N downward, 1.05N, magnitude and direction, net force on apple.

Why does an insulator has a high resistance

Answers

Sometimes it's easier to think of electrical conductance. Conductance is the opposite of resistance. It's measured in mhos. Conductors conduct electricity well. They have high conductance. Insulators don't conduct very well. They have low conductance. Because resistance is the inverse of conductance, high conductance means low resistance and vice versa. Conductors conduct electricity well. They have high conductance and low resistance. Insulators don't conduct very well. They have low conductance and high resistance. This come from my book Conceptual Physics 11th edition by Paul G. Hewitt Pearson
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