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Nat2105 [25]
4 years ago
15

Near the end of a marathon race, the first two runners are separated by a distance of 45.6 m. The front runner has a velocity of

3.1 m/s, and the second a velocity of 4.65 m/s. How many seconds earlier will the second runner reach the finish line if the front runner is 250 m from the finish line in seconds?
Physics
1 answer:
morpeh [17]4 years ago
3 0

Answer:17.08 s

Explanation:

Given

distance between First and second Runner is 45.6 m

speed of first runner(v_1)=3.1 m/s

speed of second runner(v_2)=4.65 m/s

Distance between first runner and finish line is 250 m

Second runner need to run a distance of 250+45.6=295.6 m

Time required by second runner t=\frac{295.6}{4.65}=63.56 s

time required by first runner to reach finish line=\frac{250}{3.1}=80.64 s

Thus second runner reach the finish line 80.64-63.56=17.08 s earlier

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Explanation:

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b) The resistance <em>R</em><em> </em>of the heater is

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\Rightarrow R = \dfrac{P}{I^2} = \dfrac{130\:\text{W}}{(1.08\:\text{A})^2}

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The energy from radiation can be used to cause the rupture of chemical bonds. A minimum energy of 242kJ/mol is required to break
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Answer:

The longest wavelength of radiation that passesses the necessary energy for breaking the Cl- Cl bond (in Cl2) is approximately 494.2 nm, which corresponds to the visible spectrum.

Explanation:

In order to answer this question we need to recall that the energy of a photon is given by:

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E = energy

h = Planck's constant

c = speed of light in vacuum

lambda = associated photon wavelength

In order to perform the calculations, first we need to change the units of 242kJ/mol to J. For doing this, we to divide by Avogadro's number and multiply by a 1000:

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Therefore, the wavelength for a photon to break the Cl-Cl bond in a Cl2 molecule should be 494.2 nm at most, which corresponds to the visible spectrum (The visible spectrum includes wavelengths between 400 nm and 750 nm).

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