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3 years ago

A car slows down from 80 km/h to 60 km/h in 2 seconds.

Physics

1 answer:

Andreyy893 years ago

6 0

Answer:

please mark brainlist

Explanation:

Initial speed u=80 km/h=80×185=22.22 m/s

Final speed v=60 km/h=60×185=16.67 m/s

Using v=u+at

Or 16.67=22.22+α×5

⟹ a=−1.1 m/s2

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A typical electric refrigerator has a power rating of 500 Watts, which is the rate (J/s) at which electrical energy is supplied

Goshia [24]

Answer:

The rate of heat removed from inside the refrigerator is 300 watts.

Explanation:

By the First Law of Thermodynamics and the definition of a Refrigeration Cycle, we have the following formula to determine the rate of heat removed from inside the refrigerator ( $\dot Q_{L}$ ), in watts:

$\dot Q_{L} = \dot Q_{H}-\dot W$ (1)

Where:

$\dot Q_{H}$ - Rate of heat released to the room, in watts.

$\dot W$ - Rate of electric energy needed by the refrigerator, in watts.

If we know that $\dot Q_{H} = 800\,W$ and $\dot W = 500\,W$ , then the rate of heat removed from inside the refrigerator is:

$\dot Q_{L} = \dot Q_{H}-\dot W$

$\dot Q_{L} = 300\,W$

The rate of heat removed from inside the refrigerator is 300 watts.

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3 years ago

Which measurements are equal to 321 decimeters

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4 years ago

A blue-green photon (λ = 488 nm ) is absorbed by a free hydrogen atom, initially at rest. What is the recoil speed of the hydrog

Natalka [10]

Answer:

The recoil speed is $2.207\times 10^{4} m/s$

Solution:

Wavelength of a blue-green photon, $\lambda_{BG} = 488 nm = 488\times 10^{- 9} m$

Now, the energy associated with the blue-green photon:

$E_{BG} = \frac{hc}{\lambda_{BG}}$

where

h = Planck's constant

C = speed of light ion vacuum

$E_{BG} = \frac{6.626\times 10^{- 34}\times 3\times 10^{8}}{488\times 10^{- 9}}$

$E_{BG} = 4.07\times 10^{- 19} J$

Also, we know that the recoil speed can be calculated by the KInetic energy which is equal to the Energy of the blue-green photon:

$KE_{H} =\frac{1}{2}m_{p}v_{H}$

where

$v_{H}$ = velocity of Hydrogen atom

$m_{p} = 1.67\times 10^{- 27} kg$ = mass of H-atom

Now,

$KE_{H} =\frac{1}{2}m_{p}(v_{H})^{2}$

$4.07\times 10^{- 19} =\frac{1}{2}\times 1.67\times 10^{- 27}\times (v_{H})^{2}$

$v_{H} = \sqrt(4.87\times 10^{8}) = 2.207\times 10^{4} m/s$

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3 years ago

The diagram shows a person holding a bow and arrow. Which will most likely increase the kinetic energy in this system? a not rel

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Answer:

b. Increasing the mass of the arrow.

Explanation:

The formula is K=1/2mv^2. Increasing the mass also increases the kinetic energy.

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3 years ago

Consider a string with a length of (47.5 A) cm tied at both end (like on a stringed instrument). If the frequency of the first h

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To solve this problem it is necessary to apply the concepts related to wavelength as a function of frequency and speed, as well as to determine the wavelength as a function of length.

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