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Jlenok [28]
3 years ago
15

The fossil record shows scientists that

Physics
2 answers:
erastova [34]3 years ago
4 0

tells the story of the past and shows the evolution of forms over millions of years.

Aleonysh [2.5K]3 years ago
3 0

Answer:

The  fossil record tells the story of the past and shows the evolution of forms over millions of years

Explanation:

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X rays of wavelength 0.0169 nm are directed in the positive direction of an x axis onto a target containing loosely bound electr
mamaluj [8]

Answer:

a) 4.04*10^-12m

b) 0.0209nm

c) 0.253MeV

Explanation:

The formula for Compton's scattering is given by:

\Delta \lambda=\lambda_f-\lambda_i=\frac{h}{m_oc}(1-cos\theta)

where h is the Planck's constant, m is the mass of the electron and c is the speed of light.

a) by replacing in the formula you obtain the Compton shift:

\Delta \lambda=\frac{6.62*10^{-34}Js}{(9.1*10^{-31}kg)(3*10^8m/s)}(1-cos132\°)=4.04*10^{-12}m

b) The change in photon energy is given by:

\Delta E=E_f-E_i=h\frac{c}{\lambda_f}-h\frac{c}{\lambda_i}=hc(\frac{1}{\lambda_f}-\frac{1}{\lambda_i})\\\\\lambda_f=4.04*10^{-12}m +\lambda_i=4.04*10^{-12}m+(0.0169*10^{-9}m)=2.09*10^{-11}m=0.0209nm

c) The electron Compton wavelength is 2.43 × 10-12 m. Hence you can use the Broglie's relation to compute the momentum of the electron and then the kinetic energy.

P=\frac{h}{\lambda_e}=\frac{6.62*10^{-34}Js}{2.43*10^{-12}m}=2.72*10^{-22}kgm\\

E_e=\frac{p^2}{2m_e}=\frac{(2.72*10^{-22}kgm)^2}{2(9.1*10^{-31}kg)}=4.06*10^{-14}J\\\\1J=6.242*10^{18}eV\\\\E_e=4.06*10^{-14}(6.242*10^{18}eV)=0.253MeV

5 0
3 years ago
An office heater puts out 2050 btus of energy in the form of heat per hour. given that 1 btus =1.055 kj, how many megajoules of
ivolga24 [154]
<span>Assuming continuous operation (24/7), we can say that

Energy produced : Energy per hour * 24 (number of hours in a day) - 365 (number of days in a year.

Energy per hour: 2050 * 1.055 = 2162.75 kg.

So, we proceed to calculate the results

E: 2162.75 * 24 * 365 = 18,945,690 kj per year.

Now, we transform kj to megajoule, remembering that kilo is 10*3 and mega is 1'*6, so we divide the result by 1,000 in order to get the results in megajoules, and the answer would be:

18,945.69 megajoules can be produced per year.</span>
4 0
3 years ago
Is there a sound loud enough to kill a person ?
shepuryov [24]

In space there is. Items such as a supernova will instantly end your life.

6 0
3 years ago
Read 2 more answers
A railroad freight car, mass 15,000 kg, is allowed to coast along a level track at a speed of 2.0 m/s. It collides and couples w
gayaneshka [121]

Answer:

The speed of the two cars after coupling is 0.46 m/s.

Explanation:

It is given that,

Mass of car 1, m₁ = 15,000 kg

Mass of car 2, m₂ = 50,000 kg

Speed of car 1, u₁ = 2 m/s

Initial speed of car 2, u₂ = 0

Let V is the speed of the two cars after coupling. It is the case of inelastic collision. Applying the conservation of momentum as :

m_1u_1+m_2u_2=(m_1+m_2)V

V=\dfrac{m_1u_1+m_2u_2}{(m_1+m_2)}

V=\dfrac{15000\ kg\times 2\ m/s+0}{(15000\ kg+50000\ kg)}  

V = 0.46 m/s

So, the speed of the two cars after coupling is 0.46 m/s. Hence, this is the required solution.          

3 0
3 years ago
Two cars next to each other start moving in the same direction from rest, car A accelerates at m/s2 4 for 10 s and then travels
Andre45 [30]
The answer is 145 because 100 mph is equal to 25th so 145
8 0
3 years ago
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