Which statement accurately describes dark matter?

Explanation:

It is given that,

The Displacement x of particle moving in one dimension under the action of constant force is related to the time by equation as:

[tex]x=4t^3+3t^2-5t+2[/tex]

Where,

x is in meters and t is in sec

We know that,

Velocity,

[tex]v=\dfrac{dx}{dt}\\\\v=\dfrac{d(4t^3+3t^2-5t+2)}{dt}\\\\v=12t^2+6t-5[/tex]

(a) i. t = 2 s

[tex]v=12(2)^2+6(2)-5=55\ m/s[/tex]

At t = 4 s

[tex]v=12(4)^2+6(4)-5=211\ m/s[/tex]

(b) Acceleration,

[tex]a=\dfrac{dv}{dt}\\\\a=\dfrac{d(12t^2+6t-5)}{dt}\\\\a=24t+6[/tex]

Pu t = 3 s in above equation

So,

[tex]a=24(3)+6\\\\a=78\ m/s^2[/tex]

Hence, (a) (i) v = 55 m/s (ii) v = 211 m/s and (b) 78 m/s²

Density = Mass/Volume

=> 5g/cm³ = 45kg/Volume

=> 0.005kg/cm³ = 45kg/Volume

=> Volume = (cm³×45kg)/0.005kg

=> Volume = 9000kg/cm³

5 grams fits into 45 kg 9,000 times.

Since each 5 grams occupies 1 cm³, 9,000 little packages of 5 grams must occupy 9,000 cm³ .  (That's 9 liters.)

Answer:

Alkali metals

Explanation:

Elements in this group are highly reactive, soft, lustrous and highly conductive.

An element which is highly conductive, highly reactive, soft, and lustrous is most likely an alkali metal.

Alkali metals are in group 1 of the Periodic table which means that they have only a single valence electron.

This causes them to be soft and highly reactive because:

Examples of alkali electrons include:

In conclusion therefore, alkali metals are highly reactive and soft and so the element described above is most likely an alkali metal.

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Answer:

6.0×10⁻²¹ J

Explanation:

KE = 3/2 kT,

where KE is average kinetic energy per molecule,

k is the Boltzmann constant,

and T is absolute temperature.

KE = 3/2 (1.38×10⁻²³ J/K) (18 + 273.15) K

KE = 6.0×10⁻²¹ J

Answer:

The answer is 6.0×10⁻²¹ J , because KE = 3/2 kT,  where KE is average kinetic energy per molecule,  k is the Boltzmann constant,  and T is the absolute temperature.

KE = 3/2 (1.38×10⁻²³ J/K) (18 + 273.15) K

KE = 6.0×10⁻²¹ J

Answer:

4.0

Explanation:

The following data were obtained from the question:

Force (F) = 20 N

Mass (m) = 5 kg

Acceleration (a) =.?

Force is simply defined as the product of mass and acceleration. Mathematically, it is expressed as

Force (F) = mass (m) x acceleration (a)

F = ma

With the above formula, we can obtain th acceleration of the body as follow:

Force (F) = 20 N

Mass (m) = 5 kg

Acceleration (a) =.?

F = ma

20 = 5 x a

Divide both side by 5

a = 20/5

a = 4 m/s²

Therefore, the value that will complete the last cell in the question above is 4.

Answer:

Explanation:

A concave mirror is a curved mirror that is coated outwards. The outer part of the mirror is always coated. The nature of image formed by an object placed in front of a concave mirror can be real or virtual depending on the distance of the object on the axis from the mirror. The only time the object produces a virtual image is when it is placed between the focus and the pole of the mirror. The virtual image formed is a "MAGNIFIED and upright image"

For a convex mirror, the inner part is always coated and the nature of the image formed by the object doesn't depend on the distance between the image and the mirror. No matter where the object is placed, the image formed will always be virtual, upright and DIMINISHED. This means that magnification is always less than 1.

For a plane mirror, the nature of the image produced by a plane mirror also virtual because it is always formed behind the mirror. The size of the image formed is always THE SAME as that of the object. This means that the magnification is always equal to 1.

a) In summary, the difference between virtual images produced by concave, plane, and convex mirrors is that virtual images produced by concave mirror are MAGNIFIED, virtual images produced by plane mirror are THE SAME SIZE as that of the object and virtual images produced by convex mirrors are always DIMINISHED.

b) Magnification is defined as the ratio of the image distance to the object distance. Mag = v/u

Note that object distances are always positive, hence it is only the image distance that can either be positive or negative which in turn affects the magnification causing it to be positive or negative.

Negative image distance shows that the image is virtual while positive image distance shows that the image is real.

A negative magnification therefore shows that the nature of the image is a virtual image.

Newton first law state that anything in motion or rest will remain in motion or in rest until an external force is applied

Newton third law of motion state that every action have equal and opposite reaction

Answer:

Newton's laws of motion relate an object's motion to the forces acting on it. In the first law, an object will not change its motion unless a force acts on it. ... In the third law, when two objects interact, they apply forces to each other of equal magnitude and opposite direction.

Explanation:

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Answer:

Fe = 2.4 × 10^10 N

Explanation:

Given the following :

q1 = charge 1 = 0.0072 C = positive direction

q2 = charge 2 = 0.0060 C = - ve direction

r = distance = 0.0040

Using the relation :

Fe = K(q1q2) /r^2

Where K = columb's constant = 9×10^9 Nm^2/C^2

Fe = electric force

Fe = 9×10^9(0.0072 * 0.0060) / 0.0040^2

Fe = [9×10^9 (0.0000432)] / 0.000016

Fe = 388,800 / 0.000016

Fe = 24300000000

Fe = 2.43 × 10^10 N

Answer:

Explanation:

It is the case of perfectly elastic collision . So we shall apply formula of velocity after collision as follows .

Let  m₁ and m₂ be the mass colliding with velocity u₁ and u₂ and their velocity become v₁ and v₂ after collision .

[tex]v_1=\frac{(m_1-m_2)u_1 }{m_1+m_2)} +\frac{2 m_2u_2}{(m_1+m_2)}[/tex]

Putting the values

[tex]v_1=\frac{ (.30-.80).40 }{( .30+.80)} +\frac{2\times .80\times(-.15) }{(.30+.80 )}[/tex]

= - 0.4 m /s

So direction of .30 kg mass will be reversed .

[tex]v_2=\frac{ ( m_2-m_1) u_2 }{( m_1+m_2)} +\frac{2 m_1u_1}{(m_1+m_2)}[/tex]

putting the values

[tex]v_2=\frac{ ( .80-.30)(-.15) }{( .30+.80)} +\frac{2 \times.30\times.40}{(.30+.80)}[/tex]

= .15 m /s

The direction of .80 kg will become from left to right ie its direction will be reversed .

b ) Minimum amount of kinetic energy will be at the position when they move with common velocity

common velocity

v = .3 x .4 - .8 x .15 / (.3 + .8)

= 0

c )

Missing energy is stored as elastic potential energy in the spring .

Answer:

0.4 N

Explanation:

The weight mg is 8 N, so the mass is:

mg = 8 N

m = 8 N / g

m = 8 N / (10 m/s²)

m = 0.8 kg

The force needed to accelerate it to 0.5 m/s².

F = ma

F = (0.8 kg) (0.5 m/s²)

F = 0.4 N

Answer:

Lever systems are simple machines that change or increase the input force that we apply to the load. The lever provides us with some mechanical...

Answer:

● Effort arm or Effort distance (ED): The perpendicular distance from the fulcrum to the point of effort is called effort arm.

● Load arm or Load distance (LD): The perpendicular distance from the fulcrum to the point of load is called load arm.

Answer: Bleach is a base

Explanation:  If bleach had a pH level of 12, a number above 7, than it is a base.  Hope this helps!

Answer:

distance between should be 1.25 × 10^6 m

Explanation:

Force is proportional to separation distance.

[tex]250 \: newtons = 2.5 \times {10}^{6} \: metres \\ ( \frac{1}{2} \times 250) \: newtons = d \\ \\ d = \frac{125 \times 2.5 \times {10}^{6} }{250} \\ d = 1.25 \times {10}^{6} \: metres[/tex]

Answer:

distance between should be 1.25×10^6.

Explanation:

force Is proportional to separation .

mrk above answer branilest .

Answer:

here I am just giving an idea of how the graph will be like ...

In the pic..

Hope it helped u if yes mark me BRAINLIEST!

Tysm!

:)

Answer:

Archaeology

Explanation:

Radioisotopes are radioactive atoms of an element in which their atoms contain excess energy making them unstable. When broken down they become more stable releasing radiations.

Carbon 14 is a radioactive isotope that is used in archaeology to study and estimate the lifespan and age of organic materials such as wood, leather. Carbon 14 can be used to estimate the ages of materials up to 50000 to 60000 years.

Answer:

archaeology

Explanation:

Answer:

The most accurate and precise method to measure the thickness of a coin would be by a micrometer screw guage.

The most accurate and precise method to measure the thickness of a coin is with the help of a screw gauge.

A unit of measurement is a specified magnitude of a quantity that is established and used as a standard for measuring other quantities of the same kind.

It is determined by convention or regulation.

Any additional quantity of that type can be stated as a multiple of the measurement unit.

The smallest length that a screw gauge can measure is called its least count.

Thus, if we have to measure the thickness of a coin using a screw gauge to measure a coin is the most exact and precise approach available.

Learn more about the unit of measurement here, refer to the link given below;

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Answer:

Friction

Explanation:

friction is the force that tries to slow things down when two things are rubbed together.

Answer:

That is friction don't know

Explanation:

how I know that

Answer:

Here are two security mechanisms that are widely used in electrical circuits as well as appliances.

Explanation:

Answer:

add text fully or atleast add book name edition . solution is in picture.  chk pictures ignore b part

Explanation:

Explanation:

Earth’s orbit around the Sun represented as :

1 AU = 4 inches

Therefore,

Inner edge of the Oort Cloud represented as :

10,000 AU = 40,000 / 63360 = 0.631 miles

Outer edge of the Oort Cloud represented as:

100,000 AU = 400,000 / 63360 = 6.31 miles

Explanation:

Could you also show the diagram

Answer:

F = 9.675Hz

Explanation:

pls for certain reasons let us make

3 loops : 6$/4 = L

6$/4 = 2

$ = 4/3 = 1.333

V = F x $

F = V/$

F = 12.9/1.333 = 9.675Hz

F = 9.675Hz

Answer:

b. There will be more electrons emitted.

Explanation:

In photoelectric emission, the energy of the emitted electron is dependent on the frequency of the wave incident on the plate; but not the intensity. The rate of electron emission per unit time however depends on the intensity of the incident light. So increasing the intensity of the light at constant frequency will only affect the number of electrons emitted per unit time.

Question:

What is uniform rectilinear motion?

Answer:

Uniform rectilinear motion is when an object travels at a constant speed with zero acceleration.

Answer:

the value of acceleration as a body moves with an uniform speed is zero

Answer:

Helo ....

so this answer would be First class levers

becoz...

First-class levers have a considerable practical advantage over the other types of levers. They convert a downward moving force into a lifting force

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Answer:

A)0.00966 N/C

B) counterclockwise direction

Explanation:

We are given;

Diameter of the metal ring; d = 4.3 cm

Radius;r = 2.15 cm = 0.021- m

Initial magnetic field, B = 1.12 T

Rate of decrease of the magnetic field;dB/dt = 0.23 T/s

Now, as a result of change in magnetic field, an emf will be induced in it. Thus, , electric field is induced and given by the formula :

∫E•dr = d/dt∫B.A •dA

This gives;

E(2πr) = dB/dt(πr²)

Gives;. 2E = dB/dt(r)

E = dB/dt × 2r

We are given;

E = 0.23 × 2(0.021)

E = 0.00966 N/C

The magnitude of the electric field induced in the ring has a magnitude of 0.00966 N/C

B) The direction of electric field will be in a counterclock wise direction when viewed by someone on the south pole of the magnet

Answer:

R=4Ω

Explanation:

R1 and R3 are parrallel

so we have : R=R1*R2/R1+R2

R=6*3/6+3

R=18/9

R=2Ω

R2 and 2Ω are in series,so we have

R=R2+2

R=2+2

R=4Ω