How much energy must the brakes absorb to bring a 1200kg car from 30m/s to 15 m/s?

Answer:

Acceleration, a = 0.35 m/s²

Explanation:

Given the following data;

Initial velocity, u = 3.5 m/s²

Final velocity, v = 2.1 m/s²

Time, t = 4 secs

To find the acceleration, we would use the first equation of motion;

V = u - at (the sign is negative because Lucy is slowing down).

Substituting into the formula, we have;

2.1 = 3.5 - a(4)

2.1 = 3.5 - 4a

4a = 3.5 - 2.1

4a = 1.4

a = 1.4/4

a = 0.35 m/s²

Answer:

Explanation:

any more explanation?

Answer:

B) 10^-2 cm/s

in term of meter. it is 10^-4 m/s

Explanation:

Answer:

36 times less.

Explanation:

The distance from you to the sun is 6AU's, and from the sun to the earth is 1 AU.

Therefore,

At Earth sunlight received per unit cm² is:

[tex]I_{earth} = \dfrac{I_o}{4 \pi \times (1)^2}[/tex]

[tex]I_{earth} = \dfrac{I_o}{4 \pi}[/tex]

[tex]I_{me} =\dfrac{I}{4 \pi (6)^2}[/tex]

[tex]I_{me} = \dfrac{I_o}{36(4 \pi)}[/tex]

Thus, [tex]I_{earth} = 36 \times I_{me}[/tex]

Thus, the right answer is 36 times less.

Answer:

FATS

Explanation:

Fats are made up of carbon and hydrogen elements joined together in long groups called hydrocarbons. The simplest unit of fat is the fatty acid, of which there are two types: saturated and unsaturated.

The macronutrient which is made up of carbon and hydrogen elements joined together in long groups called hydrocarbons is: D. Fats​.

A macronutrient refers to a very large molecule (structure) that comprises covalently bonded organic atoms (hydrocarbons) and smaller molecular structures (monomers).

In Science, macronutrients are grouped into four (4) main categories and these are;

Fats (Lipids) are macronutrients that are typically made up of both carbon and hydrogen elements, which are joined together in long groups referred to as hydrocarbons.

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Answer:

Explanation:

iphotosynthesis 2coal burning 3electric motor 4 electricity generator 5 waterturbines 6 solar bulb

A new planet that supports life would have all the following characteristics except an orbiting moon. Hence, option B is correct.

An enormous, spherical celestial object known as a planet is neither a star nor its remains. The nebular hypothesis, which states how an interstellar cloud falls out of a nebula to produce a young protostar encircled by a protoplanetary disk, is now the best explanation for planet formation.

By gradually accumulating material under the influence of gravity, or accretion, planets develop in this disk.

The rocky planets Mercury, Venus, Earth, and Mars, as well as the giant planets Jupiter, Saturn, Uranus, and Neptune, make up the Solar System's minimum number of eight planets. These planets all revolve around axes that are inclined relative to their respective polar axes.

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Answer:

a) 10.51 J

b) 3.48 m/s

Explanation:

Given data :

mass of train ( M ) = 2.2 kg

Given initial velocity ( u ) = 1.6 m/s

a) calculating work done by the force over the journey of the train

F = mx + b  ------ ( 1 )

m = slope  = ( Δ f / Δ x ) = 2.8 / -7.5 = - 0.373 N/m

x = distance travelled on the x axis by the train = 7.5 m

F = force experienced by the train = 2.8 N

x = 0

∴ b = 2.8

hence equation 1 can be written as

F = ( -0.373) x + 2.8   ----- ( 2 )

hence to determine the work done by the force

W   = [tex]\int\limits^7_0 { ( -0.373) x + 2.8 )} \, dx[/tex]     Note:  the limits are actually 7.5 and 0

∴ W ( work done ) = -10.49 + 21 = 10.51 J

b) calculate the speed of the train at the end of its journey

we will apply the work energy theorem

W = 1/2 m*v^2  -  1/2 m*u^2

∴ V^2 = 2 / M ( W + 1/2 M*u^2 )  ( input values into equation )

 V^2 = 12.11

hence V = 3.48 m/s

Answer:

35,000 km = 35,000,000 m = 3.5 E107 m

t = S / v = 3.5 * 10E7 / 3.0 E10E8 = .117 sec

Answer:

Explanation:

Option C is the correct answer

Some thermometers contain alcohol. Alcohol is used in thermometers because expands and contracts easily. The correct option is C.

Thermometer is the temperature measuring device which consists of a liquid in the bulb which expands as the temperature is increased.

The liquid metal used in the thermometer must have the property to respond on the hotness and coldness rapidly.

In place of mercury, some thermometers use alcohol because an alcohol has a very low freezing point as compared to the Mercury.

Thus, the correct option is C.

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Some thermometers contain alcohol. Alcohol is used in thermometers because expands and contracts easily.

Answer:

a) Battery-operated devices have: small led lights, flashlights, wireless keyboards and mice, watches, electronic weights

b) ed lights and flashlights transform into light energy and thermal energy

c)  Em₀ = U = m gh,  Em_f = K = ½ m v²

Explanation:

In this exercise ask to complete the sentences

a) Battery-operated devices have: small led lights, flashlights, wireless keyboards and mice, watches, electronic weights

b) These devices transform the chemical energy stored in the batteries into other forms of energy.

Led lights and flashlights transform into light energy and thermal energy

Keyboards transform into electromagnetic energy that is emitted

clocks transform to mechanical energy from the movement of the needles

Electronic weights transforms the chemical energy of the baria into gravitational potential energy that prevents the movement of the plate and this translates into the reading of the body weight

c) The total energy of the cylinder mechanical energy when sustained is

          Em₀ = U = m gh

it is transformed as it descends into kinetic energy, at any point

          Emₙ = K + U = 1/2 m v² + m g y

at the lowest point of the trajectory all energy is transformed

           Em_f = K = ½ m v²

Answer:

so i would say 11.4 i dont have work only this link

Explanation:

https://flexbooks.ck12.org/cbook/ck-12-physics-flexbook-2.0/section/11.4/primary/lesson/wave-speed-ms-ps

Answer:

B.

Divide the height of the valley walls by the rate of erosion.

Explanation:

There is a relationship between the rate of erosion and the hieght at which it is eroded according to Newton's law of motion. In the case of the scenario above, the best way to determine the time the river started carving the valley would be the division of the height of the valley walls by the rate of erosion.

Answer:

a. Speed = 1.6 m/s

b. Amplitude = 0.3 m

c. Speed = 1.6 m/s

Amplitude = 0.15 m

Explanation:

a.

The frequency of the wave must be equal to the reciprocal of the time taken by the boat to move from the highest point to the highest point again. This time will be twice the value of the time taken to travel from the highest point to the lowest point:

frequency = [tex]\frac{1}{2(2\ s)}[/tex] = 0.25 Hz

The wavelength of the wave is the distance between consecutive crests of wave. Therefore,

Wavelength = 6.4 m

Now, the speed of the wave is given as:

Speed = (Frequency)(Wavelength)

Speed = (0.25 Hz)(6.4 m)

Speed = 1.6 m/s

b.

Amplitude is the distance between the mean position of the wave and the extreme position. Hence, it will be half the distance between the highest and lowest point:

Amplitude = (0.5)(0.6 m)

Amplitude = 0.3 m

c.

frequency = [tex]\frac{1}{2(2\ s)}[/tex] = 0.25 Hz

Speed = (Frequency)(Wavelength)

Speed = (0.25 Hz)(6.4 m)

Speed = 1.6 m/s

Amplitude = (0.5)(0.3 m)

Amplitude = 0.15 m

Answer: A (first option)

Explanation: In general, the surface temperatures decreases with increasing distance from the sun. Any warm object in space loses heat via infrared radiation; also visible radiation if it is hot enough. The hotter is the object, the faster it loses heat. Consequently any object warmed by the Sun stays at equilibrium temperature - it warms up until the radiative heat loss equals to the heat received, and cannot get any warmer beyond that.

Answer:

Carbon dioxide controls the amount of water vapor in the atmosphere and thus the size of the greenhouse effect. Rising carbon dioxide concentrations are already causing the planet to heat up

Explanation:

Hope it helps! Correct me if I am wrong

Im sure about my answer

Answer:

390 light-years

Explanation:

50 x 7.8 =390

Answer:

what

you need to elaborate

Answer: Can you please write question clearly.

Explanation:

Answer:

so you have a question

Explanation:

either way, have a nice day

Answer:

   f = 5.3 Hz

Explanation:

To solve this problem, let's find the equation that describes the process, using Newton's second law

        ∑ F = ma

where the acceleration is

         a = [tex]\frac{d^2 y}{dt^2 }[/tex]

        B- W = m \frac{d^2 y}{dt^2 }

To solve this problem we create a change in the reference system, we place the zero at the equilibrium point

           B = W

In this frame of reference, the variable y'  when it is oscillating is positive and negative, therefore Newton's equation remains

         B’= m [tex]\frac{d^2 y'}{dt^2 }[/tex]

the thrust is given by the Archimedes relation

         B = ρ_liquid g V_liquid

the volume is

        V = π r² y'

we substitute

          - ρ_liquid g π r² y’ = m \frac{d^2 y'}{dt^2 }

          [tex]\frac{d^2 y'}{dt^2} + \rho_liquid \ g \ \pi r^2/m ) y' \ =0[/tex]

this differential equation has a solution of type

         y = A cos (wt + Ф)

where

         w² = ρ_liquid g π r² /m

angular velocity and frequency are related

         w = 2π f

we substitute

          4π² f² = ρ_liquid g π r² / m

          f = [tex]\frac{1}{2\pi } \ \sqrt{ \frac{ \rho_{liquid} \ \pi r^2 \ g}{m } }[/tex]

calculate

         f = [tex]\frac{1}{2 \pi } \sqrt{ \frac{ 1000 \ \pi \ 0.03^2 \ 9.8 }{0.025} }[/tex]

         f = 5.3 Hz

Answer:

the answer is D I tought

Answer:

a) number of copper atoms 65 (⁶⁵Cu)  is 7.692 10⁶ atoms

b) m_total Cu = 1.585 10⁹ u = 2.632 10⁻¹⁸ kg

Explanation:

a) For this exercise let's start by using the radioactive decay ratio

           N = N₀  [tex]e^{- \lambda t}[/tex]o e - lambda t

The half-life time is defined as the time it takes for half of the radioactive (activated) atoms to decay, therefore after two half-lives there are

            N = ½ (½ N₀) = ¼ N₀

            N₀ = 4 N

in each decay a photon is emitted so we can use a direct rule of proportions. If an atom emits a photon it has Eo = 1,04 Mev, how many photons it has energy E = 10,000 MeV

          # _atoms = 1 atom (photon) (E / Eo)

          # _atoms = 1 10000 / 1.04

          # _atoms = 9615,4 atoms

          N₀ = 4 #_atoms

          N₀ = 4 9615,4

          N₀=  38461.6  atoms

in the exercise indicates that half of the atoms decay in this way and the other half decays directly to the base state of Zinc, so the total number of activated atoms

          N_activated = 2 # _atoms

          N_activated = 2 38461.6

          N_activated = 76923.2

also indicates that 1% = 0.01 of the nuclei is activated by neutron bombardment

          N_activated = 0.01 N_total

          N_total = N_activated / 0.01

          N_total = 76923.2 / 100

          N_total = 7.692 10⁶ atoms

so the number of copper atoms 65 (⁶⁵Cu)  is 7.692 10⁶

b) the natural abundance of copper is

  ⁶³Cu     69.17%

  ⁶⁵Cu    30.83%

Let's use a direct proportion rule. If there are 7.692 10⁶  ⁶⁵Cu that represents 30.83, how much ⁶³Cu is there that represents 69.17%

                # _63Cu = 69.17%  (7.692 10⁶    / 30.83%)

                # _63Cu = 17.258 10⁶  atom  ⁶³Cu

the total amount of comatose is

              #_total Cu = #_ 65Cu + # _63Cu

              #_total Cu = (7.692 + 17.258) 10⁶

              #_total Cu = 24.95 10⁶

the atomic mass of copper is m_Cu = 63.546 u

          m_total = #_totalCu m_Cu

          m_total = 24.95 10⁶ 63,546 u

          m_total = 1.585 10⁹ u

let's reduce to kg

           m_total Cu = 1.585 10⁹ u (1,66054 10⁻²⁷ kg / 1 u)

           m_total Cu = 2.632 10⁻¹⁸ kg

Answer:

Explanation:

The answer is a priest or a moulana

Answer:

A: 9.8 rad/s2

B: 7.4 rad/s2

C: 8.4 rad/s2

D: 5.9 rad/s2

E: 6.5 rad/s2

I think the answer is A 9.8rad/s2

Answer:

i dont know  man

Explanation:

i dont know man

Answer: D. An AC circuit

Explanation:

I took it on a test and it was correct ; )