what is the correct definition of speed.

distance (miles or meters)

time per distance (hours per mile or seconds per meter

distance per time (miles per hour or meters per second)

time (hours or seconds)​

Answer:

A what? Is this even a question?

Explanation:

????

Answer:

A

Explanation:

In my opinion I'm pretty sure it's A because WE DO use microwaves and x-rays as techonological uses.

Answer:

A

Explanation:

Answer:

20.4

Explanation:

Given:

y₀ = 0 m

v₀ = 20.0 m/s

v = 0 m/s

a = -9.80 m/s²

Find: y

v² = v₀² + 2a (y − y₀)

(0 m/s)² = (20.0 m/s)² + 2 (-9.80 m/s²) (y − 0 m)

y = 20.4 m

It affects the colors of the sky at sunrise and sunset because only the longer-wavelengths colors are visible.

Answer:false

Explanation:

The total number of the neutrons in a atom is the difference of mass number of the atom and its atomic number.

The number of neutrons is not equal to the atomic number. Thus the given statement is false.

Atom is the smallest unit of the matter consist the positive charged nucleus and the electrons which moves around it. The atom can not be divided further.

The atom of a matter is made by three elements-

The relation between the atomic number and neutrons-

The total number of the neutrons in a atom is the difference of mass number of the atom and its atomic number.

Thus total number of the neutrons in a atom is,

[tex]N=M-n[/tex]

Here, [tex]M[/tex] is the mass number of the atom and [tex]n[/tex] is the atomic number of it.

Thus, the number of neutrons is not equal to the atomic number. Thus the given statement is false.

Learn more about the atomic number here;

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Answer:

23 m/s

Explanation:

First, find the time it takes for the car to fall 40 meters.

y = y₀ + v₀ t + ½ at²

0 = 40 + (0) t + ½ (-9.8) t²

0 = 40 − 4.9 t²

t = 2.89 s

Next, find the velocity needed to travel 65 meters in that time.

x = x₀ + v₀ t + ½ at²

65 = 0 + v₀ (2.89) + ½ (0) (2.89)²

v₀ = 22.75 m/s

Rounding to two significant figures, the car's initial speed was 23 m/s.

Answer:

The correct answer is chemical properties.

Explanation:

In a group, the chemical properties are very similar, because all the elements of the group have the same number of electrons in their last or last layers. The electronic configuration of its last layer is the same, varying only the period of the element. Alkaline earth metals are harder than alkaline metals, have brightness and are good electrical conductors; less reactive than alkalines, good reducing agents and form ionic compounds.

Have a nice day!

Answer:

"mono" and "atomic" means single atom this term is used in both physics and chemistry and it applied to the gasses as a monatomic gas

Answer and Explanation:

Good Day mate!

A monatomic molecule is that some of the elements do not have a tendency to form a molecule. Which means, the molecule of an element is made up of only one atom.  Thus, there are called as Monatomic molecule.

Some common examples of monatomic molecules :

1. Helium (He)

2. Neon (Ne)

3. Argon (Ar)

4. Xenon (Xe)

Answer:

The astronaut can throw the hammer in a direction away from the space station. While he is holding the hammer, the total momentum of the astronaut and hammer is 0 kg • m/s. According to the law of conservation of momentum, the total momentum after he throws the hammer must still be 0 kg • m/s. In order for momentum to be conserved, the astronaut will have to move in the opposite direction of the hammer, which will be toward the space station.

Explanation:found this as a verified answer on here

Answer:

He can throw the hammer in the direction opposite to the direction he wants to travel in. The hammer will exert an equal and opposite force on him, as per Newton's third law, and this will help him move towards the space station

Explane

above

Answer:

The mass of Substance D was 1 g greater than the mass of Substance B.

Explanation:

15 g of A → 5 g of B + 4 g of C + x g of D

From the law of conservation of mass, Mass of D should be x = (15 - 5 - 4 ) g = 6 g

This is 1 g more than the mass of B and 2 g more than mass of C.

Thus, correct option is The mass of Substance D was 1 g greater than the mass of Substance B.

The energy transferred is known as kinetic energy, and it depends on the mass and speed achieved. Kinetic energy can be transferred between objects and transformed into other kinds of energy.

Answer: 7071.067 Joules

Explanation:

The Work [tex]W[/tex] done by a Force [tex]F[/tex] refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path [tex]d[/tex].  

It should be noted that it is a scalar, and its unit in the International System of Units is the Joule (like energy). Therefore, 1 Joule is the work done by a force of 1 Newton when moving an object, in the direction of the force, along 1 meter:  

[tex]1J=(1N)(1m)=Nm[/tex]  

Now, when the applied force is constant and the direction of the force and the direction of the movement are parallel, the equation to calculate it is:  

[tex]W=(F)(d)[/tex] (1)

When they are not parallel, both directions form an angle, let's call it [tex]\alpha[/tex]. In that case the expression to calculate the Work is:  

[tex]W=Fdcos{\alpha}[/tex] (2)

In this case the force and the distance in the path form an angle [tex]\alpha=45\°[/tex], so we will use the second equation, where [tex]F=400N[/tex] and [tex]d=25 m[/tex]:

[tex]W=(400 N)(25 m) cos(45\°)[/tex] (3)

Then:

[tex]W=7071.067 Nm=7071.067 J[/tex]

The work done by the sailor to pull the boat 25 meters with a force of 400 newtons at a 45-degree angle to the dock is approximately 7,071 Joules.

The amount of work done by the sailor on the boat can be calculated by using the formula for work done by a force at an angle, which is W = F  imes d  imes  ext{cos}( heta). In this case, the force (F) is 400 newtons, the distance (d) is 25 meters, and the angle ( heta) is 45 degrees.

First, we calculate the cosine of the angle, which in this case is  ext{cos}(45^{ ext{o}}) =  rac{ ext{ extsqrt{2}}}{2}.

Then, we multiply the force, distance, and cosine of the angle: W = 400 N  imes 25 m  imes  rac{ ext{ extsqrt{2}}}{2}.

Therefore, the work done by the sailor is 400  imes 25  imes  rac{ ext{ extsqrt{2}}}{2}, which equals 7,071 Joules approximately.

Answer:

60 seconds

Explanation:

Given:

v₀ = 10 m/s

v = 30 m/s

Δx = 120 m

Find: t

Δx = ½ (v + v₀)t

120 = ½ (30 + 10) t

t = 60

It takes 60 seconds.

Answer:

Velocity is a change in displacement over change in time and uses the units m/s.

Both are rates of change and can be positive or negative.

Acceleration is a change in velocity over change in time and uses the units m/s².

Explanation:

Velocity is the change in displacement over change in time, this makes it a rate of change. It can be positive or negative because it is a vector quantity. It uses the units m/s because that is a displacement unit over a time unit.

Acceleration is the change in velocity over change in time, this makes it a rate of change. It can be positive or negative because it is also a vector quantity. It uses the units m/s² (m/s/s) because that is a velocity unit over a time unit.

Answer:

7÷10

Explanation:

initial velocity=7m/s

final velocity=0m/s

Answer:

-1.4 m/s²

Explanation:

The initial velocity is 7 m/s.  When the ball rolls back, its velocity is -7 m/s.

Acceleration is change in velocity over change in time.

a = Δv / Δt

a = (-7 m/s − 7 m/s) / 10 s

a = -1.4 m/s²

Answer:

Pressure is a force exerted by the substance per unit area on another substance. The pressure of a gas is the force that the gas exerts on the walls of its container. When you blow air into a balloon, the balloon expands because the pressure of air molecules is greater on the inside of the balloon than the outside.xplanation:

Answer:

Pressure is a force exerted by the substance per unit area on another substance. The pressure of a gas is the force that the gas exerts on the walls of its container. When you blow air into a balloon, the balloon expands because the pressure of air molecules is greater on the inside of the balloon than the outside.

Explanation:

Answer:cerebral cortex

Explanation:

Answer:

Cerebral Cortex

Explanation:

The cerebral cortex has a left and a right hemisphere. Each hemisphere can be divided into four lobes: the frontal lobe, temporal lobe, occipital lobe, and parietal lobe. The lobes are functional segments. They specialize in various areas of thought and memory, of planning and decision making, and of speech and sense perception.

Answer:

The length of the swimming course is 47.16 meters.

Explanation:

It is given that the right triangle overlaps the lake and hypotenuse L runs through the length of the lake. Thus length of the lake will be the length of this hypotenuse.

The instructors have conducted measurements of the right triangle and has found the legs to be 25 and 40 meters. The sum of squares of base and height of  a right triangle gives the value of its hypotenuse according to Pythagoras theorem.

Thus [tex]h^2+b^2=H^2[/tex]

b - base

h - height.

[tex]40^2+25^2=1600+625=2225[/tex]

[tex]H=\sqrt{2225}=47.16 m[/tex]

Explanation:

Newton's first law says that an object at rest stays at rest, and an object in motion stays in motion, until acted upon by an unbalanced force.

If there's no unbalanced force, then an object at rest will stay at rest.

Answer:

80 m/s

Explanation:

Given:

a = -5 m/s²

v = 0 m/s

Δx = 640 m

Find: v₀

v² = v₀² + 2a(x − x₀)

(0 m/s)² = v₀² + 2(-5 m/s²) (640 m)

v₀ = 80 m/s

Answer:

520 N

Explanation:

Work is the dot product of the force vector and displacement vector.

W = F · x

This means it is the product of the magnitudes of the vectors and the cosine of the angle between them.

W = F x cos θ

The displacement of the soil is 15 m up.  The force is parallel to the ramp.  So the angle between the vectors is 90° − 35° = 55°.

Plugging in the values and solving for F:

4500 J = F (15 m) (cos 55°)

F = 523 N

Rounded to two significant figures, the force is 520 N.

Answer:

The magnitude of the resultant vector R is 50 meters ⇒ 2nd answer

Explanation:

The resultant vector is the vector sum of two or more vectors

If the two vectors perpendicular to each other, then the magnitude of

the resultant vector is the square root of the sum of their squares

If x and y are two vectors perpendicular to each other, then the

magnitude of its resultant vector R is:

→ [tex]R=\sqrt{x^{2}+y^{2}}[/tex]

Lets solve the problem

A right triangle with the base labeled 40 meters and the height labeled

30 meters

The hypotenuse is a dotted arrow labeled R

→ The base and the height of the right triangle are perpendicular

→ The hypotenuse is the resultant vector of them

Assume that x represents the base of the triangle and y represents the

height of it

By using the rule above

→ x = 40 m , y = 30 m

→ [tex]R=\sqrt{x^{2}+y^{2}}[/tex]

→ [tex]R=\sqrt{(40)^{2}+(30)^{2}}[/tex]

→ [tex]R=\sqrt{1600+900}[/tex]

→ [tex]R=\sqrt{2500}=50[/tex]

The magnitude of the resultant vector R is 50 meters

Answer:

r ≥ R, E = Q / (4πR²ε₀)

r ≤ R, E = 12Q (⅓ (r/R)³ − ¼ (r/R)⁴) / (4πr²ε₀)

Maximum at r = ⅔ R

Maximum field of E = Q / (3πε₀R²)

Explanation:

Gauss's law states:

∮E·dA = Q/ε₀

What that means is, if you have electric field vectors E passing through areas dA, the sum of those E vector components perpendicular to the dA areas is equal to the total charge Q divided by the permittivity of space, ε₀.

a) r ≥ R

Here, we're looking at the charge contained by the entire sphere.  The surface area of the sphere is 4πR², and the charge it contains is Q.  Therefore:

E(4πR²) = Q/ε₀

E = Q / (4πR²ε₀)

b) r ≤ R

This time, we're looking at the charge contained by part of the sphere.

Imagine the sphere is actually an infinite number of shells, like Russian nesting dolls.  For any shell of radius r, the charge it contains is:

dq = ρ dV

dq = ρ (4πr²) dr

The total charge contained by the shells from 0 to r is:

q = ∫ dq

q = ∫₀ʳ ρ (4πr²) dr

q = ∫₀ʳ ρ₀ (1 − r/R) (4πr²) dr

q = 4πρ₀ ∫₀ʳ (1 − r/R) (r²) dr

q = 4πρ₀ ∫₀ʳ (r² − r³/R) dr

q = 4πρ₀ (⅓ r³ − ¼ r⁴/R) |₀ʳ

q = 4πρ₀ (⅓ r³ − ¼ r⁴/R)

Since ρ₀ = 3Q/(πR³):

q = 4π (3Q/(πR³)) (⅓ r³ − ¼ r⁴/R)

q = 12Q (⅓ (r/R)³ − ¼ (r/R)⁴)

Therefore:

E(4πr²) = 12Q (⅓ (r/R)³ − ¼ (r/R)⁴) / ε₀

E = 12Q (⅓ (r/R)³ − ¼ (r/R)⁴) / (4πr²ε₀)

When E is a maximum, dE/dr is 0.

First, simplify E:

E = 12Q (⅓ (r/R)³ − ¼ (r/R)⁴) / (4πr²ε₀)

E = Q (4 (r³/R³) − 3 (r⁴/R⁴)) / (4πr²ε₀)

E = Q (4 (r/R³) − 3 (r²/R⁴)) / (4πε₀)

Take derivative and set to 0:

dE/dr = Q (4/R³ − 6r/R⁴) / (4πε₀)

0 = Q (4/R³ − 6r/R⁴) / (4πε₀)

0 = 4/R³ − 6r/R⁴

0 = 4R − 6r

r = ⅔R

Evaluating E at r = ⅔R:

E = Q (4 (⅔R / R³) − 3 (⁴/₉R² / R⁴)) / (4πε₀)

E = Q (8 / (3R²) − 4 / (3R²)) / (4πε₀)

E = Q (4 / (3R²)) / (4πε₀)

E = Q (1 / (3R²)) / (πε₀)

E = Q / (3πε₀R²)

For question 1:

For the region [tex]r \geq R[/tex], an expression for the electric field can be calculated by using the  Gauss law:

Use gauss law of electrostatics, the charge electric flux through the Gaussian surface is,

[tex]\int \vec{E} \cdot d\vec{A}=\frac{q_{enc}}{\varepsilon_{0} }\\\\E(4\pi r^2)=\frac{Q}{\varepsilon_0}\ \ \ \ \ \ \ \ \ \ \ \ \ (Since\ \ q_{enc}=Q )[/tex]

Here, Q is the enclosed charge and [tex]\varepsilon_0[/tex] , is the permeability.

[tex]E=\frac{1}{4\pi \varepsilon_0 } \frac{Q}{r^2}[/tex]

Therefore, the required electric field is [tex]\frac{Q}{4\pi\varepsilon_0 r^2 }[/tex]

For question 2:

For Gaussian sphere of radius [tex]r \leq R[/tex], the charge enclosed within a spherical shell is,

[tex]dq =\rho_0(1-\frac{r}{R}) 4\pi r^2 dr[/tex]

Hence, the total charge enclosed with in the radius r is as follows,  

[tex]q_{enc}=\int^{r}_{0} \rho_{0} (1-\frac{r}{R}) 4\pi r^2 \ dr\\\\[/tex]

       [tex]=4\pi \rho_0 |\frac{r^3}{3}-\frac{r^4}{4R}|^4_{0}\\\\=\frac{12 Q}{R^3}(\frac{r^3}{3}-\frac{r^3}{4R})\\\\=\frac{Qr^3}{R^3}(4-\frac{3r}{R})\\\\[/tex]

Use Gauss's law for the Gaussian sphere of radius r,

[tex]\int \vec{E}\cdot dA=\frac{q_{enc}}{\varepsilon_0}\\\\E(4\pi r^2)=\frac{Qr^3}{\varepsilon_0 R^3}(4-\frac{3r}{R})\\\\E=\frac{Qr}{4\pi \varepsilon_0 R^3}(4-\frac{3r}{R})\\\\[/tex]

Therefore, the required electric field at [tex]r\leq R[/tex] is [tex]\frac{Qr}{4\pi \varepsilon_0 R^3}(4-\frac{3r}{R})\\\\[/tex]

For question 3:

The change in electric filed with respect to distance is zero when the electric field has a  maximum value.

[tex]\frac{dE}{dr}= 0\\\\\frac{d(\frac{Qr}{4\pi \varepsilon_0 R^3}(4-\frac{3r}{R}))}{dr}=0\\\\(\frac{Q}{4\pi \varepsilon_0 R^3})\frac{d(4r-\frac{3r^2}{R})}{dr}=0\\\\[/tex]

Here, [tex](\frac{Q}{4\pi \varepsilon_0 R^3})[/tex] is not equal to zero. Hence,

[tex]\frac{d(4r-\frac{3r^2}{R})}{dr}=0\\\\4-\frac{6r}{R}=0\\\\r=\frac{4R}{6}=\frac{2R}{3}[/tex]

Therefore, the required value of [tex]r \ \ is\ \ \frac{2R}{3}\\\\[/tex]

For question 4:

Maximum value of the electric filed is as follows

[tex]E= \frac{Q}{4\pi \varepsilon_0 R^3} (4-\frac{3r}{R})\\\\[/tex]

   [tex]= \frac{Q(\frac{2R}{3})}{4\pi \varepsilon_0 R^3} (4- \frac{3(\frac{2R}{3})}{R})\\\\=\frac{Q}{3 \pi \varepsilon_0 R^2}[/tex]

Therefore, the required maximum value of the electric field is [tex]\frac{Q}{3 \pi \varepsilon_0 R^2}[/tex]

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Answer:

500 newton force is needed to move a car of mass 100kg to an acceleration of 5m/s/s.

Explanation:

As we know from Newton's second law of motion that force= F = m×a

=> F = 100 × 5 = 500 N

Answer:

The Autocratic system of governance

Explanation:

This is because,in Autocratic system of governance decision making is done by only individual. And his/her decision is final.

Answer:

The Autocratic system of governance

Explanation:

Answer:

The gravitational pull is determined by the mass and distance.

Explanation:

According to Newton's law of universal gravitation

[tex]F = G\frac{m1.m2}{r^{2} }[/tex]

where F is the gravitational pull, G is gravitational constant, m₁ and m₂ are masses of bodies and r is the distance between them.

It can be seen from the above equation that F is directly proportional to the product of the masses and inversely proportional to the square of distance between them.

                      F ∝ m₁m₂

                      F ∝ 1/r²

A wave is a disturbance that travels through space and matter, characterized by its wavelength, frequency, and amplitude.

A wave is a disturbance or oscillation that travels through space and matter, transferring energy from one place to another. Waves are characterized by three main features: wavelength, frequency, and amplitude. The wavelength is the distance between two identical points on successive waves. The frequency refers to the number of wave cycles that occur in a second. The amplitude is a measure of the wave's height from the rest position.

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