Answer:
77.9 km/h
Explanation:
We determine the initial momenta of lion and gazelle.
Lion: 173 × 80.9 = 13995.7
Gazelle: 36.2 × 63.8 = 2309.56
Since they are running in the same direction, we add their momenta to get the total initial momentum:
After the collision, they are together and have a common velocity. Hence, the total final momentum is
By the principle of conservation of momentum, the total initial momentum is equal to the total final momentum, provided there are no external forces.
Answer:
λ = 4.1638 10⁻⁷ m
Explanation:
The photoelectric effect was explained by Einstein assuming that the radiation acts like particles and the equation that describes the process is
K = h f -Ф
where K is the kinetic energy of the emitted electrons, hf the energy of the photons according to Planck's equation and Ф the work function of the material
In this case they give us the kinetic energy of the electrons
K = 0.7 eV
The sodium work function is tabulated Ф = 2.28 eV
Let's find the frequency of the photons
f = (K + Ф) / h
Planck's constant is
h = 6.626 10⁻³⁴ J s (1 eV / 1.6 10⁻¹⁹ J) = 4.136 10⁻¹⁵ eV s
f = (0.7 + 2.28) / 4.136 10⁻¹⁵
f = 7.2050 10¹⁴ Hz
let's find the wavelength using the relationship between speed and frequency and wavelength
c = λ f
λ = c / f
λ = 3 10⁸ / 7.205 10¹⁴
λ = 4.1638 10⁻⁷ m
<span>The actual time to travel would be 200 miles / 60 miles/hour = 3.33333 hours or 3 hours and 20 minutes. Since the van driver has been directed to allow an extra hour, the amount of time allowed should be 4 hours and 20 minutes for the total duration of the trip to Dallas.</span>
Answer:
These low-pressure gases prevent the filament inside the bulb from burning out; it also relieves some of the stress on the glass globe from normal atmospheric pressure, lessening the chance of glass breakage.
Explanation: