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3 years ago

Forces are needed to make a car do which of these?

Physics

1 answer:

zalisa [80]3 years ago

8 0

All of the above.

if your car is on a steep hill it needs force to stop moving and to speed up

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julsineya [31]

People do be giving out free points tho

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3 years ago

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A solid sphere rolls along a horizontal, smooth surface at a constant linear speed without slipping. What is the ratio between t

dsp73

Answer:

option E

Explanation:

given,

Rotational Kinetic Energy, KE_r = $\dfrac{1}{2}I\omega^2$

Moment of inertia of the solid,

$I = \dfrac{2}{5}MR^2$

$\omega = \dfrac{V}{R}$

now,

$KE_r = \dfrac{1}{2}I\omega^2$

$KE_r = \dfrac{1}{2}\times \dfrac{2}{5}MR^2 (\dfrac{V}{R})^2$

$KE_r =\dfrac{1}{5}MV^2$ ......(1)

transnational kinetic energy

$KE_t =\dfrac{1}{2}MV^2$

Total kinetic energy

$KE = \dfrac{1}{2}MV^2 + \dfrac{1}{5} MV^2$

$KE = \dfrac{7}{10}MV^2$

ratio of rotational kinetic energy to the total kinetic energy

$\dfrac{KE_r}{KE_t}=\dfrac{\dfrac{1}{5}MV^2}{\dfrac{7}{10}MV^2}$

$\dfrac{KE_r}{KE_t}=\dfrac{2}{7}$

hence, the correct answer is option E

4 0

3 years ago

1) Which of the following alternative energy sources is NOT inexhaustible?

kakasveta [241]

1) I am pretty sure that f the following alternative energy sources which is NOT inexhaustible is <span>D.Wind Energy. I choose this option because this type of energy can not be used completely or in full measure.

2) </span><span>The problems which are associated with the increased use of nuclear energy are being revealed by all the options attached to this question. As you can see, all the issues connected to increacing of nuclear energy are represented above the question, so the answer is D.
3) </span>One problem with wind energy as a major source of electricity is D. the expense of large tracts of land in populated areas. This is the major drawback of such source of renewable energy.

7 0

3 years ago

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Please Help............................

vlada-n [284]

Protons
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7 0

4 years ago

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A capacitor consists of a set of two parallel plates of area A separated by a distance d. This capacitor is connected to a batte

vovikov84 [41]

<h2>Answer:</h2>

(e) halved

<h2>Explanation:</h2>

The electrical enery (E) stored in a capacitor is related to its capacitance (C) and potential difference (V) as follows;

E = $\frac{1}{2}$ x C x $V^{2}$ ------------------------(i)

Also, the capacitance (C) of a capacitor consisting of parallel plates is related to the area (A) of the plates and distance (d) between the plates as follows;

C = A x ε₀ / d ------------------------(ii)

Where;

ε₀ is the permittivity of free space.

Substituting equation (ii) into equation (i) gives;

E = $\frac{1}{2}$ x A x ε₀ / d x $V^{2}$ --------------------(iii)

From equation(iii)

When the potential difference (V) is constant, then the electrical energy (E) stored is <em>inversely </em>proportional to the distance between the plates. i.e

E = k / d ----------------(iv)

Where;

k = proportionality constant = $\frac{1}{2}$ x A x ε₀ x $V^{2}$ (which is the product of all constants)

Therefore from equation (iv);

=> E₁ x d₁ = E₂ x d₂ ---------------------------(v)

Where;

E₁ and E₂ are the initial and final values of the electrical energy stored.

d₁ and d₂ are the initial and final values of the distance between the plates.

<em>So, when the distance is doubled, i.e.</em>

d₂ = 2 x d₁

<em>Substitute the value of d₂ into equation (v) to give;</em>

=> E₁ x d₁ = 2 x d₁ x E₂

<em>Divide through by d₁ to give;</em>

=> E₁ = 2 x E₂

<em>Make E₂ subject of the formula</em>

=> E₂ = $\frac{1}{2}$ x E₁

Therefore, the electrical energy stored in the capacitor will be halved.

6 0

4 years ago