someone please help I can mark brainless

Answer:

A sound wave's amplitude relates to changes in pressure. The sound is perceived as louder if the amplitude increases, and softer if the amplitude decreases. This is illustrated below. DOSITS short video on amplitude.

Answer: Mature red blood cells don't have nuclei.

Explanation: " Platelets are irregularly shaped, have no nucleus, and typically measure only 2–3 micrometers in diameter. "

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Answer:

75.4

Explanation:

r= 2

h= 6

v= 22/7 *r*r*h

v= 75.42

Answer:

Time = 0.58 seconds

Explanation:

Given the following data;

Initial momentum = 3 kgm/s

Final momentum = 10 kgm/s

Force = 12 N

To find the time required for the change in momentum;

First of all, we would determine the change in momentum.

[tex] Change \; in \; momentum = final \; momentum - initial \; momentum [/tex]

[tex] Change \; in \; momentum = 10 - 3 [/tex]

Change in momentum = 7 kgm/s

Now, we can find the time required;

Note: the impulse of an object is equal to the change in momentum experienced by the object.

Mathematically, impulse (change in momentum) is given by the formula;

[tex] Impulse = force * time [/tex]

Making "time" the subject of formula, we have;

[tex] Time = \frac {impulse}{force} [/tex]

Substituting into the formula, we have;

[tex] Time = \frac {7}{12} [/tex]

Time = 0.58 seconds

Answer:

potential energy

Explanation:

this is because potential energy= mgh

so when m= 2m

p.e. = 2 times the previous value

Therefore , When mass is doubled , Potential energy gets doubled. When mass is halved , Potential energy decreases by half.

Answer: North East

Explanation: Trust me, I was just doing this on the Ck-12 and this the answer I choose and It said I'm correct.

Answer:

864 mT

Explanation:

The magnetic field due to a long straight wire B = μ₀i/2πR where μ₀ = permeability of free space = 4π × 10⁻⁷ H/m, i = current in wire, and R = distance from center of wire to point of magnetic field.

The magnitude of magnetic field due to the first wire carrying current i = 2.70 A at distance R which is mid-point between the wires is B = μ₀i/2πR.

Since the other wire also carries the same current at distance R, the magnitude of the magnetic field is B = μ₀i/2πR.

The resultant magnetic field at B is B' = B + B = 2B = 2(μ₀i/2πR) = μ₀i/πR

Now R = 2.50 cm/2 = 1.25 cm = 1.25 × 10⁻² m and i = 2.70 A.

Substituting these into B' = μ₀i/πR, we have

B' = 4π × 10⁻⁷ H/m × 2.70 A/π(1.25 × 10⁻² m)

B = 10.8/1.25 × 10⁻⁵ T

B = 8.64 × 10⁻⁵ T

B = 864 × 10⁻³ T

B = 864 mT

This question involves the concept of the magnetic field due to two current-carrying wires in the same direction, parallel to each other.

The magnitude of the magnetic field at the point P, which is equidistant from the wires is "8.64 x 10⁻⁵ T".

The following formula is used to find the magnetic field at the center distance between two parallel current-carrying wires in the same direction:

[tex]B = \frac{\mu_oI_1}{2\pi r}+\frac{\mu_oI_2}{2\pi r}\\\\But,\ I_1=I_2=I\\\\B = \frac{\mu_oI}{\pi r}[/tex]

where,

B = magnetic field at required point = ?

μ₀ = permeability of free space = 4π x 10⁻⁷ H/m

I = current = 2.7 A

r = distance from wires to the point = 2.5 cm/2 = 1.25 cm = 0.0125 m

Therefore,

[tex]B=\frac{(4\pi\ x\ 10^{-7}\ H/m)(2.7\ A)}{\pi (0.0125\ m)}[/tex]

B = 8.64 x 10⁻⁵ T

Learn more about the magnetic field here:

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Answer:

0.318cm

Explanation:

The computation of the radius of the wheel is shown below:

As we know that

One revolution of the wheel = 2πr

Here r denotes the radius of the wheel

Now

5 revolutions of the wheel would be

= 2πr ×  5

= 10πr

So,

10πr = 10cm

Thus r = 1 ÷ π

= 0.318cm

The radius of the wheel will be r=0.318 cm

The radius is defined as the distance between the center of circle and the outer layer of the circle.

It is given in the question that

Revolutions of the wheel = 5

The length of the string =10 cm

Now the radius will be calculated as

One revolution of the wheel

= [tex]2\pi r[/tex]

Now 5 revolutions of the wheel would be

=  [tex]2\pi r\times 5=10\pi\ r[/tex]

Since the string has the length of 10 cm then

[tex]10\pi\ r=10[/tex]

[tex]r=\dfrac{10}{10\pi}[/tex]

[tex]r=0.318\ cm[/tex]

Thus the radius of the wheel will be r=0.318 cm

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Answer:

bb kettle

Explanation:

it transfres electricsl to kinetic

Answer:

No.

Explanation:

Given that Kevin decides to soup up his car by replacing the car's wheels with ones that have 1.4 times the diameter of the original wheels. Note that the speedometer in a car is calibrated based on the tire's diameter and on the distance the tire covers in each revolution. (a) Will the reading of the speedometer change ?

Considering the formula

V = wr

Where

V = linear speed

W = angular speed

r = radius of the wheel.

But W = 2πrf

Where the the 2 and pi are constant. The radius of the first wheel will be small but counter balance with the larger frequency.

While the radius of the second wheel may be large but it will be of a small frequency.

We can therefore conclude that the reading on the speedometer will not change. Because speedometer will read the linear speed V.

Answer:

I think that the centre of mass is the point at which the distribution of mass is equal in all directions, and does not depend on gravitational field. Centre of gravity is the point at which the distribution of weight is equal in all directions, and does depend on gravitational field

The answer is Motion

Answer:

Force = 25 N

Explanation:

Given:

Work done = 50 J

Displacement = 2 m

Find:

Force

Computation:

Work done = Force x displacement

50 = Force x 2

Force = 25 N

Answer:

The specific heat capacity of steel is lower than the specific heat capacity of wood

Explanation:

THERE IS ONLY 1 ON MY assignment i geot dis right  please brainlyist

The specific heat capacity of steel is lower than the specific heat of a piece of wood. Therefore, option (2) is correct.

Specific heat can be defined as the heat energy required to change the temperature of one unit mass of a substance of a constant volume by 1 °C. The S.I. unit of the specific heat capacity of a material is KJ/Kg.

The thermal capacity of a material is defined as a physical property of a substance. The amount of heat is given to a given mass to create a change in unit temperature.

The mathematical expression of specific heat capacity can be written as :

Q = m C ΔT      Where C is the heat capacity.

The specific heat capacity is an intensive property of a substance as it does not depend upon the size of the material.

A steel metal fence post feels colder than a wooden fence post of similar size because the specific heat of steel is lower than the specific heat capacity of wood.

Learn more about specific heat, here:

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Answer:

15m

Explanation:

Given that a roller coaster starts from rest at A, rolls down the track to B, describes a circular loop of 12-m diameter, and travels up and down past point E. Determine the range of values of h for which the roller coaster will not leave the track at D or E. Assume no energy loss due to friction

Solution

At point A

The maximum potential energy = maximum K.E

At point A, the total energy = maximum P.E.

Down the track to point B, the P.E will be converted to maximum K.E.

Hence,

Mgh = 1/2mv^2

Also, the total energy at the roller coaster will be P.E + K.E

I.e mg2r + 1/2mv^2

Where 2r = height of the loop = diameter of the loop.

Since the energy is always conserved, hence

Mgh = mg2r + 1/2mv^2

Let also consider the centripetal acceleration to keep the object in the circle.

F = mV^2 / r = mg

Mass will cancel out

U^2 = rg

Substitute that in the last equation

Mgh = mg2r + 1/2mgr

mgh = mg ( 2r + 1/2r )

Mg will cancel out

h = 2.5r

Where r = 12/2 = 6

h = 2.5 × 6

h = 15m

Therefore, the values of h for which the roller coaster will not leave the track at D or E is 15m.

Answer:

oil heats faster

Explanation:

Answer:

Generally, the lowest overtone for a pipe open at one end and closed would be at  y / 4  where y represents lambda, the wavelength.

Since F (frequency) = c / y       Speed/wavelength

F2 / F1 = y1 / y2      because c is the same in both cases

F2 = y1/y2 * F1

F2 = 3 F1 = 750 /sec

Note that L = y1 / 4 = 3 y2 / 4 for these wavelengths to fit in the pipe

and y1 = 3 y2

The second harmonic will be three times the first harmonic. The answer is 750 Hz

Closed pipes have odd multiples of frequencies or harmonics. That is,

If  [tex]F_{0}[/tex] = fundamental frequency = first harmonic

[tex]F_{1}[/tex] = 3[tex]F_{0}[/tex] = second harmonic

[tex]F_{2}[/tex] = 5[tex]F_{0}[/tex] = third harmonic

[tex]F_{3}[/tex] = 7[tex]F_{0}[/tex] = fourth harmonic

Let assume that the first harmonic is 250 Hz, If you blow it much harder, second, third or fourth harmonic can be produced.

By using the formula above,

second harmonic will be 3 x 250 = 750Hz

Therefore, the frequency of the next harmonic heard if you blow much harder will be 750 Hz

Learn more about Sound waves here: https://brainly.com/question/1199084

Answer:

v = 12.79 m/s

Explanation:

Given that,

The mass of a car, m = 1200 kg

Momentum of the car, p = 15 350 kg-m/s

We need to find the velocity of the car. We know that, the formula for the momentum of an object is given by :

p = mv

Where

v is the velocity of the bject

So,

[tex]v=\dfrac{p}{m}\\\\v=\dfrac{15350}{1200}\\\\v=12.79\ m/s[/tex]

So, the velocity of the car is 12.79 m/s.

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Answer:

the knee extensors must exert 15.87 N

Explanation:

Given the data in the question;

mass m = 4.5 kg

radius of gyration k = 23 cm = 0.23 m

angle ∅ = 30°

∝ = 1 rad/s²

distance of 3 cm from the axis of rotation at the knee r = 3 cm = 0.03 m

using the expression;

ζ = I∝

ζ = mk²∝

we substitute

ζ = 4.5 × (0.23)² × 1

ζ  = 0.23805 N-m

so

from; ζ = rFsin∅

F = ζ / rsin∅

we substitute

F = 0.23805 / (0.03 × sin( 30 ° )

F = 0.23805 / (0.03 × 0.5)

F F = 0.23805 / 0.015

F = 15.87 N

Therefore, the knee extensors must exert 15.87 N

Answer:

the energy in the oscillations between the blocks is 3.025 J

Explanation:

Given the data in the question;

Force f = 138 N

stiffness of spring k = 605 kg/s²

mass of block = 202 g = 0.202 kg

pushing the block a distance 15 cm, the rightmost block has moved a distance 5 cm

i.e

x₁ = 15 cm

x₂ = 5cm

the energy in the oscillations between the blocks will be;

E[tex]_A[/tex] = E[tex]_B[/tex] = [tex]\frac{1}{2}[/tex]k( Δx )²

we substitute

= [tex]\frac{1}{2}[/tex] × k( 15 - 5 )² × 10⁻⁴

= [tex]\frac{1}{2}[/tex] × 605 × ( 10 )² × 10⁻⁴

= [tex]\frac{1}{2}[/tex] × 605 × 100 × 10⁻⁴

= 3.025 J

Therefore, the energy in the oscillations between the blocks is 3.025 J

Answer: I think $20 billion a year it’s worth the cost. The reasoning behind that is because we can conduct research on various things that could help out humanity. Therefore we can conclude that’s spending billions of dollars every year is worth it.

Explanation:

Answer:

Its true

Explanation:

but im answering so the other person can get brainliest :3

To everyone who sees this, have a wonderful day or night!

Answer:

247.5 N

Explanation:

From the question,

The expression of centriputal force is given as

F = mv²/r..................... Equation 1

Where m = mass of the runner, v = velocity of the runner, r = radius of the runner

Given: m = 55 kg, v = 9 m/s, r = 18 m

Substitute these values into equation 1

F = 55(9²)/18

F = 247.5 N.

Hence the centriputal force of the runner is

247.5 N

Answer:

a. True

Explanation:

Sound are mechanical waves that are highly dependent on matter for their propagation and transmission.

Sound travels faster through solids than it does through either liquids or gases. A student could verify this statement by measuring the time required for sound to travel a set distance through a solid, a liquid, and a gas.

Mathematically, the speed of a sound is given by the formula:

[tex] Speed = wavelength * frequency [/tex]

Generally, the frequency of a sound wave determines the pitch of the sound that would be heard.

Diffraction occurs for all types of waves, including sound waves.

Answer:

A

Explanation:

Gas particles move fastest.

Plasma lacks fixed volume and shape.

Liquid lacks fixed shape, but has fixed volume.

Solid has both fixed volume and shape.