The light rays in the illustration below do not properly focus at the focal point. this problem occurs with?

a. all spherical mirrors

b. all parabolic mirrors

c. only defective spherical mirrors

d. only defective parabolic mirrors

Which notation is used to represent an alpha particle? a. b. c. d.

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

Matter is needed to transfer thermal energy bya. conductionb. convectionc. radiation d. both a & b.