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4 years ago

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The drag force pushes opposite your motion as you ride a bicycle. If you double your speed, what happens to the magnitude of the

drag force? A) The drag force goes up by a factor of 4 B) The drag force stays the same. C) The drag force decreases. D) The drag force doubles as well

1 answer:

aksik [14]4 years ago

3 0

Answer:

Option A

The drag force goes up by a factor of 4

Explanation:

Fact:

Drag force is directly proportional to the square of the velocity of a moving object

Therefore, when drag force pushes opposite to the motion as one rides a bicycle, the magnitude of drag force increases by a factor of 4

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A solid sphere rolling without slipping on a horizontal surface. If the translational speed of the sphere is 2.00 m/s, what is i

koban [17]

Answer:

The total kinetic energy is 2.8m J. (NOTE: m is mass of the sphere)

Explanation:

The total kinetic energy of a sphere is given by the sum of the rotational kinetic energy and the translational kinetic energy. That is,

$K_{Total} = K_{R} + K_{T}$

The rotational kinetic energy $K_{R}$ is given by

$K_{R} = \frac{1}{2}I\omega^{2}$

Where $I$ is the moment of inertia

and $\omega$ is the angular velocity

The translational kinetic energy $K_{T}$ is given by

$K_{T} = \frac{1}{2}mv^{2}$

Where $m$ is the mass

and $v$ is the translational speed (velocity)

∴ $K_{Total} = \frac{1}{2}I\omega^{2} + \frac{1}{2}mv^{2}$

But, the moment of inertia $I$ of a sphere is given by

$I = \frac{2}{5}mr^{2}$

Where $m$ is mass

and $r$ is radius

∴ $K_{Total} = \frac{1}{2}\times \frac{2}{5}mr^{2} \omega^{2} + \frac{1}{2}mv^{2}$

$K_{Total} = \frac{1}{5}mr^{2} \omega^{2} + \frac{1}{2}mv^{2}$

Also, $\omega = \frac{v}{r}$

∴ $\omega^{2} = \frac{v^{2} }{r^{2} }$

Then,

$K_{Total} = \frac{1}{5}mr^{2} \times \frac{v^{2} }{r^{2} } + \frac{1}{2}mv^{2}$

$K_{Total} = \frac{1}{5}mv^{2} + \frac{1}{2}mv^{2}$

∴ $K_{Total} = \frac{7}{10}mv^{2}$

From the question, $v = 2.00 m/s$

Then,

$K_{Total} = \frac{7}{10}m(2.00)^{2}$

$K_{Total} = \frac{7}{10}m\times 4.00$

$K_{Total} = 2.8m J$

Hence, the total kinetic energy is 2.8m J. (NOTE: m is mass of the sphere)

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3 years ago

The slowest type of mass movement, Which involves the lifting and contracting of soil particles overtime, is called

finlep [7]

Answer should be Creep.

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3 years ago

Actinium-226 has a half-life of 29 hours. If 10g of actinium-226 disintegrates over a period of 145 hours,

Masteriza [31]

Answer: d) 312.5 mg

Explanation:

This problem can be solved using the Radioactive Half Life Formula:

$A=A_{o}.2^{\frac{-t}{h}}$

Where:

$A$ is the remaining amount of Actinium-226

$A_{o}=10 g$ is the initial amount of Actinium-226

$t=145 h$ is the time elapsed

$h=29 h$ is the half life of Actinium-226

Knowing this, let's find $A$ :

$A=(10 g) (2)^{\frac{-145 h}{29 h}}$

$A=0.3125 g \frac{1000 mg}{1 g}=312.5 mg$

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3 years ago

Most of an atom is empty space.<br> a. True<br> b. False

Iteru [2.4K]

<span>Yes, the vast majority of an atom is indeed empty space. Most of it's mass is centered in the nucleus. Flying around the nucleus are the electrons, but they're very very far away (on an atomic level anyway). Most of the atom is the space between the nucleus and the electrons.</span>

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3 years ago

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A beam oflight is reflected off a mirror. If the angle of incidence is 30 degrees, according to the Law of Reflection the angle

zaharov [31]

Answer:

30°

Explanation:

According to the second law of reflection, it States that the angle of incidence i is equal to the angle of reflection r.

The angle of incidence is known to be the angle between the incident ray and the normal.

The Angle of reflection is the angle between the reflected ray and the normal.

This normal ray is a ray that is perpendicular to the surface.

According to the question, if the beam of light is reflected off the surface and its angle of incidence is 30°, its angle of reflection will also be 30° i.e i=r = 30°

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4 years ago