I need help with science homework

Answer:

a

Explanation:

because it can increase anything

Answer:                                                                              

Explanation:(40.0)×(9.8)=392

764N-392=372

Answer:

He should swim at least three times a week at the community pool to build stamina.

Explanation:

The temperature of the rock located at 1,000 km below the earth' surface has been 3200 degree Celsius. Thus, option D is correct.

The temperature at the earth's surface has been found to be nearly 0 degree Celsius. According to the geology of the earth, the temperature has been increased to 1500 degree Celsius by digging 100 km below the earth surface.

Thus, the temperature at 100 km from earth surface has been 1500 degree Celsius.

On moving down from 100 km, there has been a rise in temperature, and at the mouth of the mantle at 1000 km, the temperature has been approximately 3500 degree Celsius.

Thus the temperature that has been near  about 3500 degree Celsius is 3200 degree Celsius. Thus, the temperature of the rock at 1000 km below the earth surface has been 3200 degree Celsius. Thus, option D is correct.

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Answer:

The kilogram (kg) is defined by taking the fixed numerical value of the Planck constant h to be 6.62607015 ×10−34 when expressed in the unit J s, which is equal to kg m2 s−1, where the meter and the second are defined in terms of c and ∆νCs.

Answer:

The radius of the circle made by the person on the merry go round is 74.55 meters

Explanation:

The given parameters are;

The force the merry go round exerts on the rider = 1000 N

The time it takes the merry go round to make one complete revolution = 15 seconds

The weight of the person = 750 N

The radius of the circle made by the person on the merry go round = r

We have;

[tex]F_c = \dfrac{m \cdot v^2}{r} = m \cdot \omega ^2 \cdot r[/tex]

Where;

m = The mass of the person

v = The velocity of the person

[tex]F_c[/tex] = The centrifugal force acting on the person = 1,000 N

r = The radius of the circle made by the person on the merry go round

ω = Angular velocity = 2·π/15 rad/s

We have;

The mass of the person = The weight/(The acceleration due to gravity, g)

∴ The mass of the person = 750/9.81 ≈ 76.45 kg

By substituting the calculated and known values into the equation for  the centripetal force, we have;

[tex]F_c[/tex] = m × ω² × r

1000 = 76.45 × (2·π/15)² × r

r = 1000/(76.45 × (2·π/15)²) = 74.55 m

The radius of the circle made by the person on the merry go round = r = 74.55 m.

Answer:

When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral.

Explanation:

An atom has an equal quantity of positive and negative electric charges (the protons and electrons) when its electron and proton counts are equal (the protons). Since the atom has a total electric charge of zero, it is referred regarded as being neutral.

The atom is the smallest unit of matter that may be divided without resulting in electrically charged particles. Additionally, it is the tiniest substance with features like chemical elements. The atom is therefore the basic building block of chemistry.

Examine different electron arrangements in the electron shells that surround an atom's nucleus.

Examine different electron arrangements in the electron shells that surround an atom's nucleus. The rest is made up of a cloud of negatively charged electrons surrounding a positively charged nucleus made up of protons and neutrons. Compared to electrons, which are the lightest charged particles in nature, the nucleus is small and dense.

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Answer:

i dont know dude but ask someone who is in your grade lol

Explanation:

Answer:

The answer is "False"

Explanation:

The geologic time scale is the "schedule" for occasions in Earth history. It partitions time into named units of unique time called in descending order of duration "eons, eras, periods, epochs, and ages". The specification of those geologic time units depends on stratigraphy, which is the relationship and order of rock layers. The fossil structures that happen in the stones, nonetheless, give the central methods for setting up a geologic time scale, with the circumstance of the development and vanishing of far and wide species from the fossil record being used to outline the beginnings and endings of ages,, periods, and different stretches.

Geologic time is the broad time period involved by the geologic history of Earth. Formal geologic time starts toward the beginning of the Archean Eon (4.0 billion to 2.5 billion years back) and proceeds to the current day.

Answer:

1320 Hz

Explanation:

The third harmonic is given as 3fo, where fo is the fundamental frequency.

The fundamental frequency is the lowest frequency that can occur in a pipe. In an open pipe, both even and odd harmonics occur which are multiples of the fundamental frequency fo. Hence the harmonics in an open pipe are; 2fo, 3fo,4fo..... etc.

For the third harmonic; 3fo = 3 (440 Hz) = 1320 Hz

Answer:

8.5m/s

Explanation:

Using the equation of motion

v² = u² + 2gH

v is the final speed of the diver

u  is the initial speed of the diver

g is the acceleration due to gravity

H is the height of the object

Given the following

V = 1.3m/s

H = 3.60m

g = 9.8m/s²

Required

Initial speed of the diver u

Substitute the given values into the formula:

v² = u² -2gH

1.3² = u²  - 2(9.8)(3.60)

1.69 = u²-70.56

u² = 1.69+70.56

u² = 72.25

u = √72.25

u = 8.5m/s

Hence the diver's speed, in m/s, just before she enters the water is 8.5m/s

Answer:

radius of a circle is measured by an instrument, so it is the independent variable

Explanation:

The independent variable corresponds to the magnitude controlled by the experimenter and in general can be measured by an instrument.

The dependent variable is the variable used to perform the calculations, obtained from a mathematical transformation of the independent variable.

The radius of a circle is measured by an instrument, so it is the independent variable and the area is calculated by

         A = π r²

Therefore the area corresponds to the dependent variable

Answer:

ohh yes. answer is true

Answer:

t=0.0625s

Explanation:

F=number of swings/time taken

DATA

Frequency=4.0Hz

number of swings from Q to R

=1/4

time taken=?

Frequency=number of swings/time taken

make t the subject of the formula

t=n/f

substitute the given date

t=0.25/4.0

t=0.0625s

option A is collect

Explanation:

causes hallucinations

causes lung cancer eg cigarettes

causes bad breath

damages the nervous system eg cocaine

Explanation:

Drug use can lead to an addiction. Effects of

drugs on the body can slowly destroy vital

systems and functions. Drug dependence can quickly begin to affect your psychological and physical health, and can also affect your work and social life.

hope it helps!

F = ma

= 10kg × 2m/s

= 20N

Answer : 20N

Explanation :

F = Force (N)

m = mass (kg)

a = acceleration (m/s)

Answer:

Actually, the sun goes a bit down, like it's not all the way up as to summer. How I know is that you actually can go online maybe search for some videos and see proof, I don't really know how to explain it.

Explanation:

Reason #1: If you check, go out for 12 hours and see, I think the sun is a little down.

Reason #2:

The earth’s axis is tilted.

From a Brainly user of this question for more info:

The Earth is NOT farther away from the sun in USA Winter, and NOT closer to the sun in USA Summer. In 2021, we will be NEAREST to the sun on January 2, and FARTHEST from the sun on July 5 !

NEAREST to the sun next Saturday.

FARTHEST from the sun next July 5.

Answer:

frictional force acting on the cart 450 N.

Given:

mass of cart = 50 kg

acceleration = 3

To find:

Frictional force = ?

Formula used:

F -  = 600 N

F = ma

= frictional force

Solution:

Force on the block is given by,

F -  = 600 N

F = ma

= frictional force

= 600 - m a

= 600 - (50 × 3)

= 600- 150

= 450 N

According to the given data the frictional force acting on the cart 450 N.

Explanation:

Kinetic Energy

= 0.5mv²

= 0.5(900kg)(25m/s)²

= 281,250J.

Answer:

V = 3.65 m/s

Explanation:

Explanation:

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Answer: 1.6 N

Explanation:

The weight of an object is calculated as:

W = g*m

where:

g = gravitational acceleration = 9.8m/s^2

m = mass of the object.

We also know that:

mass = density*volume.

or:

m = d*v

Let's start:

The weight of the beaker is 0.4N

And the weight of the beaker filled with water is 1.4N

Then the weight of the water alone will be:

1.4N - 0.4N = 1N = (d*v)*9.8m/s^2

And we know that the density of the water is:

1 g/cm^3

But we are working with Newtons, then we need to rewrite this with kilograms as the mass unit, we can use that:

1000g = 1kg

Now we can rewrite the density as:

d = 1 g/cm^3 = 1*(1/1000) kg/cm^3 = 0.001 kg/cm^3

Replacing that in the above equation, we get:

With this, we can find the volume that the water occupies.

W = 1 N = v* 0.001 kg/cm^3*9.8m/s^2

       1 N /( 0.001 kg/cm^3*9.8m/s^2 ) = 102.04 cm^3.

Now, when we fill it with a brine with a density of 1.2 g/cm^3, the mass of this brine in a volume of  102.04 cm^3 be:

M = (1.2 g/cm^3)*( 102.04 cm^3) = 122.448 g

Rewriting this in kg we get:

M = 122.448 g = (122.448/1000) kg = 0.122448 kg

Then the weight of this brine is:

M = 0.122448 kg*9.8m/s^2 = 1.2 N

And the beaker weighs 0.4N, then the beaker filled with this brine will weight:

1.2 N + 0.4N = 1.6 N

Answer:

Explanation:

According to Newton's second law

F = ma

m is the mass = 0.12kg

a is the acceleration = v-u/t

a = 5-0/0.6

a = 5/0.6

a = 8.333m/s²

Get the force

F = 0.12 * 8.333

F = 1.0N

Hence the average resultant force acting on the ball while it is being hit is 1.0N

Answer:

v=69.32 m/s

Explanation:

you have to transfer the distance from mile to meters (from miles to meters multiply by 1609)

so d=204387 m

you have to transfer the time from hour to second (from hour to second multiply by 3600)

so t=2948.4 s

the rule says v=d/t=204387/2948.4= 69.32 m/s

The TGV train has a speed of 69.306 meters per second.

Let suppose that TGV train is travelling at uniform velocity, then we can be calculated its speed by means of the following kinematic equation:

[tex]v = \frac{x}{t}[/tex] (1)

Where:

Now we proceed to convert both distance and time in terms of fundamental units:

Distance:

[tex]x = 127\,mi \times 1609\,\frac{m}{mi}[/tex]

[tex]x = 204343\,m[/tex]

Time:

[tex]t = 0.819\,h \times 3600\,\frac{s}{h}[/tex]

[tex]t = 2948.4\,s[/tex]

If we know that [tex]x = 204343\,m[/tex] and [tex]t = 2948.4\,s[/tex], then the speed of the TGV train is:

[tex]v = \frac{204343\,m}{2948.4\,s}[/tex]

[tex]v = 69.306\,\frac{m}{s}[/tex]

The TGV train has a speed of 69.306 meters per second.

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