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3 years ago

True or false compounds can have repaying elements

Physics

1 answer:

Sindrei [870]3 years ago

7 0

True, Compounds can contain different types of elements.

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A heavy solid disk rotating freely and slowed only by friction applied at its outer edge takes 120 seconds to come to a stop.

alisha [4.7K]

Answer:

The time is 16 min.

Explanation:

Given that,

Time = 120 sec

We need to calculate the moment of inertia

Using formula of moment of inertia

$I=\dfrac{1}{2}MR^2$

If the disk had twice the radius and twice the mass

The new moment of inertia

$I'=\dfrac{1}{2}\times2M\times(2R)^2$

$I'=8I$

We know,

The torque is

$\tau=F\times R$

We need to calculate the initial rotation acceleration

Using formula of acceleration

$\alpha=\dfrac{\tau}{I}$

Put the value in to the formula

$\alpha=\dfrac{F\times R}{\dfrac{1}{2}MR^2}$

$\alpha=\dfrac{2F}{MR}$

We need to calculate the new rotation acceleration

Using formula of acceleration

$\alpha'=\dfrac{\tau}{I'}$

Put the value in to the formula

$\alpha=\dfrac{F\times R}{8\times\dfrac{1}{2}MR^2}$

$\alpha=\dfrac{2F}{8MR}$

$\alpha=\dfrac{\alpha}{8}$

Rotation speed is same.

We need to calculate the time

Using formula angular velocity

$\Omega=\omega'$

$\alpha\time t=\alpha'\times t'$

Put the value into the formula

$\alpha\times120=\dfrac{\alpha}{8}\times t'$

$t'=960\ sec$

$t'=16\ min$

Hence, The time is 16 min.

5 0

3 years ago

A student writes the following script for a scene in a futuristic movie: A rocket ship is landing on the Moon where many astrona

Sav [38]

Answer: No crash landing on the surface of the moon and there is no vibration due to low acceleration due to gravity.

Explanation:

The rocket ship can't land on the surface of the moon because it depends on winged flight for its controlled descent to the surface of the Earth. Since the moon has no real atmosphere, the wings would not be able to glide the craft smoothly to the moon's surface.

The acceleration due to gravity in the moon is very low compared to the earth. The astronauts cannot experience vibration ripple through the Moon’s surface beneath their feet because the low level acceleration due to gravity will drastically affect the weight of the ship.

6 0

3 years ago

Do only number 3 and thank

IrinaK [193]

Charge = 0.2 Ah is the correct answer...