Anucleus of radioactive radium (226ra), initially at rest, decays into a radon nucleus (222rn) and an alpha-particle (a 4he nucleus). if the kinetic energy of the alpha-particle is 6.72 × 10−13 j, what is (a) the recoil speed of the radon nucleus, and (b) its kinetic energy? the superscripts indicate, roughly, the mass of each nucleus in unified mass units (u), where 1 u = 1.66 × 10−27 k

Samir watches a 100-minute movie on his spaceship. maria's spaceshipe flies in the same direction as samir's spaceship but she observes his move to last 125 minutes and his spaceship to be 40 m long. how long does samir observe his own spaceship to be? according to an observer on earth, planet x is stationary. maria and samir depart earth on their spaceships at the same time, each flying at 0.5c. maria flies toward planet x and samir flies in the opposite direction. according to maria, her voyage to planet x takes 9 years. how many years does marias voyage take according to samir?

Which lists the organs in the correct order as food passes from the mouth to anus?

The star betelgeuse is about 600 light-years away. if it explodes tonight, a. we'll know because debris from the explosion will rain down on us from space.b. we'll know it immediately because it will be brighter than the full moon in the sky.c. we won't know about it until 600 years from now.d. none of the above.