As new-forming stars grow by gravitationally attracting more material, they become brighter. If a star becomes too bright, the radiation pressure from the star prevents gravity from pulling in more material. What power output PP would a star with a mass 35.135.1 times that of our Sun need to have in order to be unable to pull in a 3.96 μg3.96 μg dust particle of radius rp=0.935 mm, rp=0.935 mm, assuming the particle absorbs all the light incident on its πr2pπrp2 cross‑section? The mass ⊙M⊙ of the Sun is 1.99×1030 kg,1.99×1030 kg, and the gravitational constant GG equals 6.67×10−11 m3/(kg·s2).

Porque crees que el agua no podia subir mas de 10 m de altura con ese tipo de bomba

Suppose that an electromagnetic wave which is linearly polarized along the x−axis is propagating in vacuum along the z−axis. the wave is incident on a conductor which is placed at z > 0 region of the space. the conductor has conductivity σ, magnetic permeability µ and electric permittivity ε. (a) find the characteristic time for the free charge density which dissipates at the conductor. (b) write the maxwell equations and derive the wave equation for a plane wave propagating in a conductor. (c) find the attenuation distance at which the incident amplitude reduces to e ^−1 of its initial value. (d) find the electric and magnetic fields inside the conductor. 8 (e) find the power loss per area of the incident electromagnetic wave at the surface of conductor.

What is the average speed of a car that travels 40 mph for 1 hour and 60 mph in another hour?