Aman has a concave mirror with focal length of 0.4m. how far should the mirror be held from his face in order to give an image of two magnification?

Is there a point between a 10 nc charge and a 20 nc charge at which the electric field is zero?

By what primary heat transfer mechanism does the sun warm the earth?

In an old-fashioned amusement park ride, passengers stand inside a 3.0-m-tall, 5.0-m-diameter hollow steel cylinder with their backs against the wall. the cylinder begins to rotate about a vertical axis. then the floor on which the passengers are standing suddenly drops away! if all goes well, the passengers will “stick” to the wall and not slide. clothing has a static coefficient of friction against steel in the range 0.60 to 1.0 and a kinetic coefficient in the range 0.40 to 0.70. part a what is the minimum rotational frequency, in rpm, for which the ride is safe? express your answer using two significant figures. f f = rpm