The objective lens in a dvd player must move quickly to keep the laser beam focused on the disc's reflective layer. why must this lens have a very small mass?

Two thin 80.0- cm rods are oriented at right angles to each other. each rod has one end at the origin of the coordinates, and one of them extends along the x- axis while the other extends along the yaxis. the rod along the x- axis carries a charge of - 15.0 μ c distributed uniformly along its length, and the other rod carries 15.0 μ c uniformly over its length. find the magnitude and direction of the net electrical force that these two rods exert on an electron located at the point (40.0 cm, 40.0 cm). (e

Part a determine the magnitude of the x component of f using scalar notation. fx f x = nothing lb request answer part b determine the magnitude of the y component of f using scalar notation. fy f y = nothing lb request answer part c determine the magnitude of the z component of f using scalar notation. fz f z = nothing lb request answer provide feedback figure1 of 1a force vector acting on a ring attached to the ground is shown in the xyz space together with its x, y, and z components lying on the corresponding positive axes. the ring is located at the origin. force f is located in the first octant. f makes an angle of 60 degrees with its x component and an angle of 45 degrees with its y component. a force vector acting on a ring attached to the ground is shown in the xyz space together with its x, y, and z components lying on the corresponding positive axes. the ring is located at the origin. force f is located in the first octant. f makes an angle of 60 degrees with its x component and an angle of 45 degrees with its y component.

Individuals who live below the poverty line get seriously ill more often than those who do not what could be the hidden variable in this situation?