The density of a substance equals its mass

Of the more than 2,000 known minerals approximately 95% of them belong to what mineral group?

Temka [501]

Your answer is Silicates.

5 0

3 years ago

Describe J.J Thomson's plum pudding model,and explain how it compares to the modern day atomic theory.

juin [17]

The correct answer to this open question is the following.

The J.J Thomson's plum pudding model establishes that when he researched the atom, he found that electrons are positively charged. Because he observed that electrons were embedded like plums. Electrons are negative. However, compared to the modern-day atomic theory, scientist Ernest Rutherford established that the space between an atom is empty, the nucleus of the atom is positive, and negative electrons have fixed motion paths.

8 0

3 years ago

Read 2 more answers

You could use an elevator or the stairs to lift a box to tenth floor.which has greater power?

erastova [34]

Stairs don't have any power at all. All the energy used to climb them
has to come from your muscles.

An elevator gets its power from the electric motors that lift it. All YOU
have to do is stand there and look around.

All of this is a big part of the reason why elevators have become so
popular, and why no buildings with more than a few floors were built
before elevators were invented.

7 0

3 years ago

What mediums are best for light waves?

ycow [4]

The strength of the electric and magnetic fields there is no physical "distance" of oscillation here. nothing is actually moving up and down if you draw light as a sinusoidal wave, the up and down motion is the strength of the EM fields cheers

4 0

3 years ago

Starting from rest, a disk rotates about its central axis with constant angular acceleration. In 1.00 s, it rotates 21.0 rad. Du

ELEN [110]

With constant angular acceleration $\alpha$ , the disk achieves an angular velocity $\omega$ at time $t$ according to

$\omega=\alpha t$

and angular displacement $\theta$ according to

$\theta=\dfrac12\alpha t^2$

a. So after 1.00 s, having rotated 21.0 rad, it must have undergone an acceleration of

$21.0\,\mathrm{rad}=\dfrac12\alpha(1.00\,\mathrm s)^2\implies\alpha=42.0\dfrac{\rm rad}{\mathrm s^2}$

b. Under constant acceleration, the average angular velocity is equivalent to

$\omega_{\rm avg}=\dfrac{\omega_f+\omega_i}2$

where $\omega_f$ and $\omega_i$ are the final and initial angular velocities, respectively. Then

$\omega_{\rm avg}=\dfrac{\left(42.0\frac{\rm rad}{\mathrm s^2}\right)(1.00\,\mathrm s)}2=42.0\dfrac{\rm rad}{\rm s}$

c. After 1.00 s, the disk has instantaneous angular velocity

$\omega=\left(42.0\dfrac{\rm rad}{\mathrm s^2}\right)(1.00\,\mathrm s)=42.0\dfrac{\rm rad}{\rm s}$

d. During the next 1.00 s, the disk will start moving with the angular velocity $\omega_0$ equal to the one found in part (c). Ignoring the 21.0 rad it had rotated in the first 1.00 s interval, the disk will rotate by angle $\theta$ according to

$\theta=\omega_0t+\dfrac12\alpha t^2$

which would be equal to

$\theta=\left(42.0\dfrac{\rm rad}{\rm s}\right)(1.00\,\mathrm s)+\dfrac12\left(42.0\dfrac{\rm rad}{\mathrm s^2}\right)(1.00\,\mathrm s)^2=63.0\,\mathrm{rad}$

5 0

3 years ago