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Two wheels having the same radius and mass rotate at the same angular velocity. One wheel is made with spokes so nearly all the

Mazyrski [523]

Answer:

C. The wheel with spokes has about twice the KE.

Explanation:

Given that

Mass , radius and the angular speed for both the wheels are same.

radius = r

Mass = m

Angular speed = ω

The angular kinetic energy KE given as

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

I=Moment of inertia for wheels

Wheel made of spokes

I₁ = m r²

Wheel like a disk

I₂ = 0.5 m r²

Now by comparing kinetic energy

$\dfrac{KE_1}{KE_2}=\dfrac{I_1}{I_2}$

$\dfrac{KE_1}{KE_2}=\dfrac{mr^2}{0.5mr^2}$

$\dfrac{KE_1}{KE_2}=2$

KE₁= 2 KE₂

Therefore answer is C.

5 0

3 years ago

The thermal transfer of energy by electromagnetic waves through the vacuum of space is called

Olenka [21]

Answer: Radiation

Explanation:

There are three ways in which the thermal transfer occurs:

1. By Conduction, when the transmission is by the direct contact.

2. By Convection, heat transfer in fluids (like water or the air, for example).

3. By Radiation, by the electromagnetic waves (they can travel through any medium and in vacumm)

So, in the outter space is vacuum, this means the energy cannot be transmitted by convection, nor conduction. It must be transmitted by electromagnetic waves that are able to travel with or without a medium, and this is called radiation.

4 0

3 years ago

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Low-frequency red light is used in dark rooms because it does not expose the film. This is because the red light has a low

Alex

energy. It will not disrupt the picture developing process by overexposing too much light on the film.

4 0

3 years ago

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A straight line is drawn on the surface of a 14-cm-radius turntable from the center to the perimeter. A bug crawls along this li

sleet_krkn [62]

Answer:

v = $\left[\begin{array}{c}0.66&0\end{array}\right]$ m/s

Explanation:

The position vector r of the bug with linear velocity v and angular velocity ω in the laboratory frame is given by:

$\overrightarrow{r}=vtcos(\omega t)\hat{x}+vtsin(\omega t)\hat{y}$

The velocity vector v is the first derivative of the position vector r with respect to time:

$\overrightarrow{v}=[vcos(\omega t)-\omega vtsin(\omega t)]\hat{x}+[vsin(\omega t)+\omega vtcos(\omega t)]\hat{y}$

The given values are:

$t=\frac{x}{v}=\frac{14}{3.8}=3.7 s$

$\omega=\frac{45\times2\pi}{60s}=4.7\frac{1}{s}$

8 0

3 years ago

A proton is 0.9 meters away from a 1.4 C charge. What is the magnitude of the electric force between the proton and the charge

Digiron [165]

Answer:

F = 2.49 x 10⁻⁹ N

Explanation:

The electrostatic force between two charged bodies is given by Colomb's Law:

$F = \frac{kq_1q_2}{r^2}\\$

where,

F = Electrostatic Force = ?

k = colomb's constant = 9 x 10⁹ N.m²/C²

q₁ = charge on proton = 1.6 x 10⁻¹⁹ C

q₂ = second charge = 1.4 C

r = distace between charges = 0.9 m

Therefore,

$F = \frac{(9\ x\ 10^9\ N.m^2/C^2)(1.6\ x\ 10^{-19}\ C)(1.4\ C)}{(0.9\ m)^2}$

F = 2.49 x 10⁻⁹ N

8 0

3 years ago

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