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3 years ago

When one observes the phase of matter of water, one observes a property of matter.

1 answer:

8 0

Water is a very unique substance because it can exist in all three phases of matter (solid, liquid, gas) within the normal temperature ranges found on Earth. When one observes the phase of matter of water, one observes a property of matter.

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When the play button is pressed, a CD accelerates uniformly from rest to 450 rev/min in 3.0 revolutions. If the CD has a radius

Marina CMI [18]

To solve this problem it is necessary to apply the kinematic equations of angular motion.

Torque from the rotational movement is defined as

$\tau = I\alpha$

where

I = Moment of inertia $\rightarrow \frac{1}{2}mr^2$ For a disk

$\alpha =$ Angular acceleration

The angular acceleration at the same time can be defined as function of angular velocity and angular displacement (Without considering time) through the expression:

$2 \alpha \theta = \omega_f^2-\omega_i^2$

Where

$\omega_{f,i} =$ Final and Initial Angular velocity

$\alpha =$ Angular acceleration

$\theta =$ Angular displacement

Our values are given as

$\omega_i = 0 rad/s$

$\omega_f = 450rev/min (\frac{1min}{60s})(\frac{2\pi rad}{1rev})$

$\omega_f = 47.12rad/s$

$\theta = 3 rev (\frac{2\pi rad}{1rev}) \rightarrow 6\pi rad$

$r = 7cm = 7*10^{-2}m$

$m = 17g = 17*10^{-3}kg$

Using the expression of angular acceleration we can find the to then find the torque, that is,

$2\alpha\theta=\omega_f^2-\omega_i^2$

$\alpha=\frac{\omega_f^2-\omega_i^2}{2\theta}$

$\alpha = \frac{47.12^2-0^2}{2*6\pi}$

$\alpha = 58.89rad/s^2$

With the expression of the acceleration found it is now necessary to replace it on the torque equation and the respective moment of inertia for the disk, so

$\tau = I\alpha$

$\tau = (\frac{1}{2}mr^2)\alpha$

$\tau = (\frac{1}{2}(17*10^{-3})(7*10^{-2})^2)(58.89)$

$\tau = 0.00245N\cdot m \approx 2.45*10^{-3}N\cdot m$

Therefore the torque exerted on it is $2.45*10^{-3}N\cdot m$

3 0

3 years ago

Select the phrases that correctly describe density. Density is a chemical property. Density relates a mass to its volume. Densit

sp2606 [1]

Answer:

Density relates a mass to its volume.

Density varies with temperature

Density determines if a substance floats or sinks.

Density may have units of grams per milliliter (g/mL)

Explanation:

Density $D$ is a characteristic property of a substance or material and is defined as the relationship between the mass $m$ of a body or substance and the volume $V$ it occupies:

$D=\frac{m}{V}$

This means the density is inversely proportional to the volume.

On the other hand, density is a scalar quantity and according to the International System of Units its unit is $D=\frac{kg}{m^{3}}$ , although it can be also expressed in $\frac{g}{ml}$ .

It should be noted that the density of a body is related to its buoyancy, a substance or body will float on another fluid if its density is lower. In addition, if the pressure of the substance remains constant, as the temperature increases, the density decreases; this means density varies with the temperature as well.

5 0

3 years ago

A 5 kg rock falls from an 8 m high cliff. What is the speed of the rock when it hits the ground?

Levart [38]

Answer:

3k mph

Explanation:

don't take my answer it is wrong

3 0

3 years ago

If a substance absorbs energy but its temperature does not change, then the internal energy is changing.

Fed [463]