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4 years ago

Which substance is a combination of different atoms?

Physics

1 answer:

zvonat [6]4 years ago

6 0

Answer:

Heterogeneous

Explanation:

A chemical substance is composed of one type of atom or molecule. A mixture is composed of different types of atoms or molecules that are not chemically bonded. A heterogeneous mixture is a mixture of two or more chemical substances where the various components can be visually distinguished.

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The great lakes in north american hold about what percent of earth's fresh surface water?

fenix001 [56]

The answer is 20 percent

8 0

3 years ago

What is the weight of a 48 kg girl on Earth? Rounded to the nearest whole number

Levart [38]

Answer:

471 N

Explanation:

Weight is just another word for the force of gravity.

Weight is a force that acts at all times on all objects near Earth. The Earth pulls on all objects with a force of gravity downward toward the center of the Earth (g-9.81 m/s2)

so we can simply say

weight =mass * gravitaitonal acceleraition

= 48 * 9.81

=470.88 N

= 471 N

6 0

3 years ago

Read 2 more answers

A bicycle racer rides from a starting marker to a turnaround marker at 10 m/s. She then rides back along the same route from the

andrew11 [14]

Given :

A bicycle racer rides from a starting marker to a turnaround marker at 10 m/s.

She then rides back along the same route from the turnaround marker to the starting marker at 25 m/s.

To Find :

Her average speed for the whole race.

Solution :

We know, average velocity is given by :

$Average \ Velocity = \dfrac{v_1 + v_2}{2}\\\\Average\ Velocity = \dfrac{10 + 25}{2}\\\\Average \ Velocity = \dfrac{35}{2}\\\\Average \ Velocity = 17.5 \ m/s$

Therefore, average speed for the whole race is given by 17.5 m/s.

3 0

3 years ago

A rotating object has an angular acceleration of α = 0 rad/s2. Which one or more of the following three statements is consistent

Murrr4er [49]

Answer:

A,B and C

Explanation:

Statement A

At all times, angular velocity is $\omega = 0\,{\rm{rad/s}$

Angular acceleration is the rate of change in angular velocity with respect to time.

Angular velocity and angular acceleration are related by

${\omega _{\rm{f}}} = {\omega _{\rm{i}}} + \alpha t$

Which when re-arranged becomes

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

There’s no change in angular velocity anytime when the angular velocity is $\omega = 0\,{\rm{rad/s}}$

The equation can be modified as follows:

$\begin{array}{c}\\\alpha = \frac{{0\,{\rm{rad/s}} - 0\,{\rm{rad/s}}}}{t}\\\\ = 0\\\end{array}$

Therefore, the angular acceleration becomes zero hence statement A is valid.

Statement B

Angular acceleration is the rate of change in angular velocity with respect to time.

Angular velocity and angular acceleration are related by

${\omega _{\rm{f}}} = {\omega _{\rm{i}}} + \alpha t$

Which when re-arranged becomes

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

There’s no change in angular velocity anytime when the angular velocity is $\omega = 10\,{\rm{rad/s}}$ .The final and initial velocities remain the same.

The equation can be modified as follows:

$\begin{array}{c}\\\alpha = \frac{{10\,{\rm{rad/s}} - 10\,{\rm{rad/s}}}}{t}\\\\ = 0\\\end{array}$

Therefore, the angular acceleration becomes zero and statement B is valid

Statement C

Angular velocity is defined as the change in the angular position with respect to time.

Angular velocity and angular displacement are related by

$\theta = \omega t$

Which can also be modified as:

${\theta _{\rm{f}}} - {\theta _{\rm{i}}}$

Note that the final position is ${\theta _{\rm{f}}}$ and initial position is ${\theta _{\rm{i}}}$

Modifying the equation to find the angular velocity we obtain

$\omega = \frac{{{\theta _{\rm{f}}} - {\theta _{\rm{i}}}}}{t}$

When the angular displacement has the same value at all times, the equation becomes

$\begin{array}{c}\\\omega = \frac{{{\theta _{\rm{i}}} - {\theta _{\rm{i}}}}}{t}\\\\ = 0\\\end{array}$

The angular velocity becomes zero.

Angular acceleration and angular velocity are related by

${\omega _{\rm{f}}} = {\omega _{\rm{i}}} + \alpha t$

The expression above can be rearranged as follows:

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

At all times, the angular velocity is $\omega = 0\,{\rm{rad/s}}$ hence initial and final velocities remain the same

We obtain

$\begin{array}{c}\\\alpha = \frac{{0\,{\rm{rad/s}} - 0\,{\rm{rad/s}}}}{t}\\\\ = 0\\\end{array}$

Therefore, the angular acceleration becomes zero and statement C is valid.

Therefore, statements A,B and C are consistent .

4 0

3 years ago

Monochromatic light falls on two very narrow slits 0.048 mm apart. Successive fringes on a screen 6.50 m away are 8.5 cm apart n

vfiekz [6]

Answer:

The wavelength is $\lambda = 6.28 *10^{-7}=628 nm$

The frequency is $f = 4.78 Hz$

Explanation:

From the question we are told that

The slit distance is $d = 0.048 \ mm = 4.8 *0^{-5}\ m$

The distance from the screen is $D = 6.50 \ m$

The distance between fringes is $Y = 8.5 \ cm = 0.085 \ m$

Generally the distance between the fringes for a two slit interference is mathematically represented as

$Y = \frac{\lambda * D}{d}$

=> $\lambda = \frac{Y * d }{D}$

substituting values

$\lambda = \frac{0.085 * 4.8*10^{-5} }{6.50 }$

$\lambda = 6.27 *10^{-7}=628 nm$

Generally the frequency of the light is mathematically represented as

$f = \frac{c}{\lambda }$

where c is the speed of light with values

$c = 3.0 *10^{8} \ m/s$

substituting values

$f = \frac{3.0*10^8}{6.28 *10^{-7}}$

$f = 4.78 Hz$

3 0

3 years ago