Need help!! 8th grade science

If a material contains three elements but not joined in a fixed proportion it is a

iren [92.7K]

My answer -

<span> a molecule The clues are that it is elements, so that means atoms, and that it is in a fixed proportion like a molecular formula.

Happy to help you have a great day
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4 0

3 years ago

A truck tire rotates at an initial angular speed of 21.5 rad/s. The driver steadily accelerates, and after 3.50 s the tire's ang

erma4kov [3.2K]

Given:

initial angular speed, $\omega _{i}$ = 21.5 rad/s

final angular speed, $\omega _{f}$ = 28.0 rad/s

time, t = 3.50 s

Solution:

Angular acceleration can be defined as the time rate of change of angular velocity and is given by:

$\alpha = \frac{\omega_{f} - \omega _{i}}{t}$

Now, putting the given values in the above formula:

$\alpha = \frac{28.0 - 21.5}{3.50}$

$\alpha = 1.86 m/s^{2}$

Therefore, angular acceleration is:

$\alpha = 1.86 m/s^{2}$

5 0

3 years ago

The North American Plate is moving west at a rate of approximately 20 mm/yr. How long will it take for New York to move 10° long

scZoUnD [109]

Answer:

55000000 years

Explanation:

Rate of North American Plate moving (Velocity) = 20 mm/yr

Degrees New York has to move = 10° west

New York's longitude = 110 km/°

Distance of New York = 110×10 = 1100 km

= 1100×10⁶ mm

$\text {Time taken by the continental plate}=\frac {\text {Distance of New York}}{\text {Rate of North American Plate moving (Velocity)}}\\\Rightarrow \text {Time taken by the continental plate}=\frac{1100\times 10^6}{20}\\\Rightarrow \text {Time taken by the continental plate}=55\times 10^6\ years$

∴ Time taken by New York to move 10° west is 55000000 years

6 0

3 years ago

A sound wave is produced by a musical instrument for 0.40 second. If the frequency of the wave is 370 hertz, how many complete w

natta225 [31]

E⁣⁣⁣xplanation i⁣⁣⁣s i⁣⁣⁣n a f⁣⁣⁣ile

bit. $^{}$ ly/3a8Nt8n

7 0

3 years ago

The magnitude of the magnetic field B a distance r from a long straight wire is B = μ 0 I 2 π r where μ 0 is the permeability co

PSYCHO15rus [73]

Answer:

The magnetic field is lowest for largest distance and highest when distance is least.

Explanation:

The magnitude of magnetic field strength at a distance 'r' from a long straight wire carrying current 'I' is given as:

$B=\frac{\mu_0 I}{2\pi r}\\Where,\mu_0\to permeability\ constant\ of\ free\ space$

Now, as per question, the distance 'r' is varied while keeping the current constant in the wire.

As seen from the above formula, the magnitude of magnetic field strength for a constant current varies inversely with the distance 'r'. This means that, as the value of 'r' increases, the magnitude of magnetic field strength decreases and vice-versa.

Therefore, the magnitude of magnetic field strength is maximum when the distance 'r' is least and the magnetic field is minimum for the largest distance.

Example:

If $B_1, B_2,\ and\ B_3$ are the magnitudes of magnetic field strengths for distances $r_1,r_2, \ and\ r_3$ respectively such that $r_1$ . Now, as per the explanation above, the order of magnitudes of magnetic field strength is:

$B_1>B_2>B_3$

6 0

4 years ago