why does a stone sink and a ship float

Answer:

42g

Explanation:

the mass of a body is given by

m=weight/gravity

=420/10

=42

I hope this helps

Answer:

Yes, this is true.

-- While the apple is falling, the same gravitational force acts on both the apple and the Earth.

-- The mass of the apple is somewhere in the neighborhood of 1/4 kg.

-- The mass of the Earth is about 5.972 x 10²⁴ kg.

-- Since the Earth has roughly 2.389 x 10²⁶ times as much mass as the apple has, the apple has roughly 2.389 x 10²⁶ greater acceleration than the Earth has, and moves roughly 2.389 x 10²⁶ times as far down as the Earth moves up, before they smack together.

-- That's why you don't notice the Earth's motion.

-- Also, you're standing on the Earth, moving up with it, toward the apple.  Maybe it would be different if you were sitting on the apple, riding it down to the ground, and you were able to notice the motion of the ground coming up to meet you at a speed that's 0.00000000000000000000000000419 of YOUR speed.  

Answer From Gauth Math

Answer:

Explanation:

We are basically needing to solve for the time in the equation d = rt, where d is the distance around Mars (aka the circumference), r is the velocity, and t is time. We need to find the circumference and the velocity. We will begin with the velocity.

Because the gravitational attraction between Phobos and Mars provides the centripetal acceleration necessary to keep Phobos in its (sort of) circular path, the equation we use for this is:

[tex]F_g=F_c[/tex] which says that Force supplied by gravity is equal to the centripetal force. Expanding that:

[tex]\frac{Gm_{Phobos}m_{Mars}}{r^2}=\frac{m_{Phobos}v^2}{r}[/tex]

When we move that around mathematically to solve for the velocity value, what we end up with is:

[tex]v=\sqrt{\frac{Gm_{Mars}}{r}[/tex] and filling in:

[tex]v=\sqrt{\frac{(6.67*10^{-11})(6.42*10^{23})}{9.38*10^6} }[/tex] and we get that

v = 2100 m/s

Now for the circumference:

C = 2πr and

C = 2(3.1415)(9.38 × 10⁶) so

C = 5.9 × 10⁷

Putting that all together in the C = vT equation:

5.9 × 10⁷ = 2100T so

T = 2.8 × 10⁴ sec or 7.8 hours

Answer:

250 Pa or N/m^2

Explanation:

Pressure(P)=F/A=500/2=250 Pa or N/m^2

When,a man stands still on a moving walkway that is going at a speed of 0.2 m/s to the west,then the velocity of the man according to a stationary observer would be 0.2 m/s west,Therefore, the correct answer would be option B.

The total displacement covered by any object per unit of time is known as velocity. The velocity of an object is depend on the magnitude as well as the direction of the object.

the mathematical expression for velocity is given by

velocity = total displacement /time

The speed and velocity of the object are very different from each other because speed does not depend upon the direction of the moving  object but velocity depends on the magnitude of speed as well as the direction of the moving object.

As per given in the problem a man stands still on a moving walkway that is going at a speed of 0.2 m/s to the west therefore from the perspective  of a stationary observer the velocity of man would be 0.2 m/s towards West.

Hence the correct options for the problem would be option B.

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Explanation:

tilting it will raise the height of its center of gravity.

Answer:

simple machine, any of several devices with few or no moving parts that are used to modify motion and the magnitude of a force in order to perform work. ... The simple machines are the inclined plane, lever, wedge, wheel and axle, pulley, and screw.

The answer to the digits rounded to one significant figure is 100.

Significant figures are the most important figures in a number of digits.

The closer a digit is to the beginning of a number, the more important  or significant  it is.

But, the rule for rounding up a set of numbers to the first significant or to one significant figure is that:

From the numbers 98.907, 9 is the most significant digit followed by 8.

8 is greater than 5 so we should round up by adding one to 9 making the number 100.

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Answer:

Joule

Explanation:

the unit of work is Joule determined by the letter J.

Answer:

Explanation:

Joule is defined as the work done by a force of one newton causing a displacement of one meter. Sometimes, newton-metre (N-m) is also used for measuring work.

Answer:

C

Explanation:

Answer:

A)

Explanation:

it keeps the electric current flowing in one direction

Answer:

Pressure and velocity are inversely proportional to each other because if pressure increase, the velocity decrease to keep the algebraic sum of potential energy, kinetic energy and pressure constant.

Answer:

Yes but no

Explanation:

Here the kid cant say that he has created s magnetic field as iron fillings do not have magnetic properties

Answer:

The number of turns in the solenoid is 19506.

Explanation:

Length of solenoid, L = 0.28 m

Magnetic field, B = 7 T

Current, I = 80 A

Let the number of turns is N.

The formula used to find the magnetic field is

[tex]B = \frac{\mu 0N I}{L}\\\\7 = \frac{4 \times 3.14\times 10^{-7}\times N\times 80}{0.28}\\\\N = 19506[/tex]

Let F₁ and F₂ denote the two forces, and R the resultant force.

F₁ and F₂ point perpendicularly to one another, so their dot product is

F₁ • F₂ = 0

We're given that one of these vectors, say F₁, makes an angle with R of 30°, so that

F₁ • R = ||F₁|| ||R|| cos(30°)

But we also have

F₁ • R = F₁ • (F₁ + F₂) = (F₁ • F₁) + (F₁ • F₂) = F₁ • F₁ = ||F₁||²

So, knowing that ||R|| = 100 N, we get that

(100 N) ||F₁|| cos(30°) = ||F₁||²

(100 N) cos(30°) = ||F₁||

||F₁|| ≈ 86.6 N

(And the same would be true for F₂.)

Answer:

Obeying to weights & measurement regulations in both national and international metrology legislation, standards and test procedures is a requirement to participate in any market because it's aimed to safeguard the consumers and promote fair competition, which provides efficiency and saves unnecessary costs to U.S. businesses and stakeholders.

Explanation:

In the U.S., the National Institute of Standards and Technology (NIST) has an Office of Weights and Measures (OWM) that represents the country in the International Organization of Legal Metrology (OIML)

Answer:

The maximum current which can flow through a fuse without melting it, is called its rating. ... If current higher than 8 A flows through the fuse, it would melt and circuit gets broken. ... Hence, fuse acts as a safety device

Answer:

The guy above me is right

Explanation:

Answer:

To convert 400 mm to m you can apply the formula [m] = [mm] / 1000; use 400 for mm. Thus, the conversion 400 mm m is the result of dividing 400 by 1000. 0.4

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Answer

Resistivity R = K * L / A    where resistivity is constant for material, L the length of the material and A the area of the material

K = R * A / L     where R is the resistance of the material

Flourine is an element which has 9 electrons. The first energy level can only hold upto 2 electrons so therefore two electrons of the fluorine element will be in the first orbital.

In the second orbital there will be seven electrons. The configuration will be as 1s2, 2s2 , 2p5 .

The first orbital has capacity of two electrons and then the remaining two electrons will be in higher second energy level.

The further 5 electrons will be in lower second energy level which is denoted by p.

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Answer:

#1. 5

#2.They have valence electrons in the same energy level.

#3. Helium atoms have 2 valence electrons, while atoms of the other elements in the group all have 8 valence electrons.

#4. cesium (Cs)

#5.  There are two electrons in the first energy level and seven electrons in the second energy level.

Explanation:

Answer:

This is because these metals are used for minting (making) coins.

Answer:

It is bcz it is used for making coins

Answer:

I'm over halfway through it so don't have a complete answer but i think you just need to keep ontop of everything and write down all the key equations on flashcards or something and aim to learn them at the beginning of each topic. i found the longer questions hard so recommend practising those

Explanation:

Answer:

Below

Explanation:

To solve for d rearrange the formula v = (d)(t) to:

  d = v / t

I'm not to sure if you are using different variables but usually in physics the formula for velocity is v = d / t not v = dt

If you wanted to solve for displacement you would do:

  d = (v)(t)

Hope this helps!

Answer:

Torque; τ = 4.712 × 10^(-3) J

Magnetic moment; M = 0.0248 J/T

Explanation:

Torque is gotten from the formula;

τ = BIA

Where;

B is magnetic field

I is current

A is area

We are given;

B = 0.19T

I = 6.2A

Rectangle dimensions = 5cm by 8cm = 0.05m by 0.08m

Thus;

Area; A = 0.05m × 0.08m = 0.004 m²

Thus;

τ = 0.19 × 6.2 × 0.004

τ = 4.712 × 10^(-3) J

Formula for the magnetic moment is given by;

M = IA

M = 6.2 × 0.004

M = 0.0248 J/T

Answer:

vf²=vi²+2a∆x

Explanation:

The third equation of motion gives the final velocity of an object under uniform acceleration given the distance traveled and an initial velocity: v 2 = v 0 2 + 2 a d . v^2=v_0^2+2ad. v2=v02+2ad. The graph of the motion of the object.

Answer:

D) crystalline solid that conducts current under certain conditions

Explanation:

A semiconductor is any crystalline solid material whose electrical conductivity is intermediary between that of insulators and conductors. That is, a semiconductor does not conduct like a conductor but does more than an insulator.

Based on this, a semiconductor is said to only conduct electricity under certain conditions as opposed to conductors that do so under any condition. Example of semiconductors are silicon, carbon, antimony, arsenic etc.

Answer:

define 1 second time

One second is the time that elapses during 9,192,631,770 (9.192631770 x 10 9 ) cycles of the radiation produced by the transition between two levels of the cesium 133 atom. ... One second is equal to 1/86,400 of a mean solar day.

Answer:

One part of 86400 part of a day is called one second time.

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Answer:

9 lần

Explanation:

Answer:

Kinetic energy (k.e) varies directly as v² from the formula

K.E=(mv²/2)

if v=3 then K.e =v²=(3)²=9