Mark's physics book is on the desk. Mark pushes horizontally (from the side) on the book, but the book does not move. Diagram A shows a box with a downward and upward arrow equal in size Diagram B shows a box with an arrow up, down, left, and right all equal in size. Diagram C shows a box with shortest arrow pointing left, equal arrows pointing up and down, and longest arrow pointing right. Diagram D shows a box with a downward and upward arrow with the downward arrow larger in size. Which force diagram represents the force on the physics book? You may neglect air resistance.

Two point charges are on the y axis. a 3.90-µc charge is located at y = 1.25 cm, and a -2.4-µc charge is located at y = −1.80 cm. (a) find the total electric potential at the origin. v (b) find the total electric potential at the point whose coordinates are (1.50 cm, 0). v

Which composition of water moves to begin a deepwater current?

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