A 560 Hz tuning fork and a piano key are struck together, and four beats are heard. When a 572 Hz tuning fork and the same piano key are struck, eight beats are heard. What is the frequency of the piano key? 564 Hz
556 Hz
572 Hz
560 Hz

Which changes would result in a decrease in the gravitational force btween two objects? check all that apply

If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.

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