PLEASE HELP ME I AM TIMED!

Answer:

t = 0.28 seconds

Explanation:

Given that,

Force acting on a firework, F = 700 N

The momentum of the firework, p =200 kg-m/s

We need to find the time before it explodes. Ket the time be t. We know that, the rate of change of momentum is equal to external frce. So,

[tex]F=\dfrac{P}{t}\\\\t=\dfrac{P}{F}\\\\t=\dfrac{200}{700}\\t=0.28\ s[/tex]

So, the required time is equal to 0.28 seconds.

Answer:

The ratio of apparent increase in volume of the liquid per unit rise of temperature to the original volume is called its coefficient of apparent expansion. ... Thus a liquid has two coefficients of expansion. Measurement of the expansion of a liquid must account for the expansion of the container as well.

Answer:

40.6°

Explanation:

The angle of refraction, when light passes from air into water at an angle of 60° from the normal, is 40.6°

It states that the ratio of sine of angle of incidence and angle of refraction is equal to the refractive index of second medium to the first medium.

sini/sinr =n₂ / n₁

Given, the light passes from air into water at an angle of 60° from the normal, the angle of incidence i = 60°, refractive index of air n₁ =1, refractive index of water n₂ = 1.333, then the angle of refraction is

sinr = sini x (n₁/n₂)

Plug the values, we get

sinr = sin60 x (1/1.333)

sinr = 40.6°

The angle of refraction is less than angle of incidence due to refraction.

Thus, the angle of refraction is 40.6°

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I also need help on this question

Answer:

Ok.............

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Answer:

please put a picture, i dont know what you are doing so i cant help.

Explanation:

Answer:

Explanation:

Performing physical activities helps to build a healthy relationship with yourself, in the sense that physical activity promotes health at all levels. Health is a set of physical, mental and social well-being, so physical activity reaches all these levels and increases the quality of life for a person as a whole.

There are several types of physical activities that can be performed and you can choose the one that best fits your preferences and routine. A walk for example can be done in any safe place and at any time and it already helps in improving physical conditioning, in receiving serotonin and endorphins, in reducing blood pressure and protecting the heart and in improving mental health.

So the ideal is for each person to set their own goals in relation to their health and seek to achieve them, either to have a better quality of life, to socialize more with people, to prevent diseases, etc.

Physical exercise helps build relationship by:

This is known to be any physical activities such as walking, running, etc., that is often done so as to keep the body fit.

It is very important when as it helps one to maintain a good balance of mental health. As a person moves their body, there is the release of endorphins that functions to make us feel good and helps handle the effects of stress and anxiety. The more a person exercise, the less mental health cases and more happier relationships.

Note that Values are the drive force of  your actions and they push or motivate as you set your life goals. They help to eliminate any obstacle in term of foreign ideas that are against one's value and it keeps one's focus on the goal.

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Answer

?????

Explanation:

Answer:

electrons move around nucleus in specific regions

We have that the correct statement that summarizes atoms over time will be

The discovery of new evidence resulted in changes to the atomic theory.

Option B

Generally

The Image shows that in the early 1800 the knowledge of atom was limited and it increased over time and by 1920 it had gone through a 4 stages of modifications to the atomic model

Therefore the correct statement that summarizes atoms over time will be

The discovery of new evidence resulted in changes to the atomic theory

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Answer:

Sam's average velocity for the entire walk is approximately;

0.075 km/min

Explanation:

The given parameters of the Lake Loop Trail are;

The distance of the trail Sam takes his dog to walk around = 5-km

From the table for the position and time, we have;

[tex]\begin{array}{ccc}Position \ (km) &&Time \ (min)\\0&&0\\1&&12\\2&&22\\3&&33\\4&&54\\5&&67\end{array}[/tex]

Plotting the given points gives the attached chart created with Microsoft Excel

The coordinates of the points are A(0,0), B(67, 5), C(67, 0)

By the definition of average velocity, we have;

[tex]Average \ velocity = \dfrac{Total \ distance}{Total \ time \ taken}[/tex]

From the plot of the points therefore, we have;

[tex]Average \ velocity= \dfrac{Length \ of BC}{The \ time \ elapsed \ between \ AC} = \dfrac{5 \ km - 0 \ km}{67 \ min - 0 \ min} = \dfrac{5 \ km}{67 \ min} \approx 0.075 \ km/min[/tex]Therefore;

Sam walked at an average velocity of approximately 0.075 km/min.

Answer:

the answer for the question is the last option

Answer:

the correct answer would be D

Explanation:

D is the correctly balanced

Answer:65.28

Explanation:

A long string has a standing wave with 2 loops at a frequency. The speed of the waves in the string is 65.28 m/s

The frequency is the number of cycles completed per second.

Given the length of the string l = is 1.70 m, no of loops n =2, frequency of wave f =38.4 Hz, then the speed of the waves is

f = nv /2l

Substitute the following values, we get

v = 38.4 x 2 x 1.70 / 2

v =65.28 m/s

Thus, the speed of the waves in the string is 65.28 m/s.

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Answer:

The term "aerobic" refers to the body's ability to provide energy through the use of oxygen.  The term anaerobic refers to the body's ability to provide energy without the use of oxygen.

An example of an aerobic exercise is swimming. An example of an anaerobic exercise is sprinting.

Explanation:

Answer:

An example of an aerobic exercise is swimming. An example of an anaerobic exercise is sprinting.

Explanation:

Answer:

a = 4 m/s²

Explanation:

Given: 28 N, 7 kg

To find: Acceleration (a)

Solution: To find (a), divide force by weight

A = F ÷ m

=  28 ÷  7

= 4 m/s²

Newtons are derived units, equal to 1 kg-m/s². In other words, a single Newton is equal to the force needed to accelerate one kilogram one meter per second squared.

Answer:

45 degrees༼ つ ◕_◕ ༽つ

Explanation:

Answer:

imma have to say C I'm not sure tho

Answer:

B

Explanation:

atoms with equal or similar electronegativity form covalent bonds in which the valence electrons are shared between the two atom

During the formation of a chemical bond, the expected result is that the electrons will complete a noble gas configuration in both atoms. Hence, option (C) is correct.

The given problem is based on the concepts and fundamentals of chemical bonds. The chemical bonds between the two atomic species is formed by sharing the electrons.

Thus, we can conclude that during the formation of a chemical bond, the expected result is that the electrons will complete a noble gas configuration in both atoms. Hence, option (C) is correct.

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Answer:

Depth and density of the liquid determine the amount of pressure in a liquid.

Explanation:

Answer:

Explanation:

Explanation: total displacement =3√2m. and total distance covered=14m. I hope this is right and helps u.

Answer:

It is the point at which electrons separate from the nucleus of atoms. It is the point at which electrons separate from the nucleus of atoms. It is theoretically the point at which all particle motion stops. ... It occurs at 273 degrees Kelvin. ... It is the point at which protons separate from neutrons in the nucleus.

Explanation:

Answer:

The speed of the student just before she lands, v₂ is approximately 8.225 m/s

Explanation:

The given parameters are;

The mass of the physic student, m = 43.0 kg

The height at which the student is standing, h = 12.0 m

The radius of the wheel, r = 0.300 m

The moment of inertia of the wheel, I = 9.60 kg·m²

The initial potential energy of the female student, P.E.₁ = m·g·h₁

Where;

m = 43.0 kg

g = The acceleration due to gravity ≈ 9.81 m/s²

h = 12.0 h

∴ P.E.₁ = 43 kg × 9.81 m/s² × 12.0 m = 5061.96 J

The kinetic rotational energy of the wheel and kinetic energy of the student supporting herself from the rope she grabs and steps off the roof, K₁, is given as follows;

[tex]K_1 = \dfrac{1}{2} \cdot m \cdot v_{1}^2+\dfrac{1}{2} \cdot I \cdot \omega_{1}^2[/tex]

The initial kinetic energy, 1/2·m·v₁² and the initial kinetic rotational energy, 1/2·m·ω₁² are 0

∴ K₁ = 0 + 0 = 0

The final potential energy of the student when lands. P.E.₂ = m·g·h₂ = 0

Where;

h₂ = 0 m

The final kinetic energy, K₂, of the wheel and student is give as follows;

[tex]K_2 = \dfrac{1}{2} \cdot m \cdot v_{2}^2+\dfrac{1}{2} \cdot I \cdot \omega_{2}^2[/tex]

Where;

v₂ = The speed of the student just before she lands

ω₂ = The angular velocity of the wheel just before she lands

By the conservation of energy, we have;

P.E.₁ + K₁ = P.E.₂ + K₂

∴ m·g·h₁ + [tex]\dfrac{1}{2} \cdot m \cdot v_{1}^2+\dfrac{1}{2} \cdot I \cdot \omega_{1}^2[/tex] = m·g·h₂ + [tex]\dfrac{1}{2} \cdot m \cdot v_{2}^2+\dfrac{1}{2} \cdot I \cdot \omega_{2}^2[/tex]

Where;

ω₂ = v₂/r

∴ 5061.96 J + 0 = 0 + [tex]\dfrac{1}{2} \times 43.0 \, kg \times v_{2}^2+\dfrac{1}{2} \times 9.60 \, kg\cdot m^2 \cdot \left (\dfrac{v_2}{0.300 \, m} }\right ) ^2[/tex]

5,061.96 J = 21.5 kg × v₂² + 53.[tex]\overline 3[/tex] kg × v₂² = 21.5 kg × v₂² + 160/3 kg × v₂²

v₂² = 5,061.96 J/(21.5 kg + 160/3 kg) ≈ 67.643118 m²/s²

v₂ ≈ √(67.643118 m²/s²) ≈ 8.22454363 m/s

The speed of the student just before she lands, v₂ ≈ 8.225 m/s.

Answer:

pH value is between 6.5 and 6.8

Explanation:

Explanation:

Milk fresh from the cow typically has a pH between 6.5 and 6.7. The pH of milk changes over

Answer:

They travel

Explanation:

Because they move in a certin way