Which of the following is an example of heat transfer by convection?

a. Water within a pan is heated and flows in a circular path.
b. Seawater is drawn into a mid-ocean ridge, heated, and rises.
c. The rise of material beneath mid-ocean ridges is coupled with subduction.

Crowbar of 5 metre is used to lift an object of 800 metre if the effort arm is 200cm calculate the force applied

If the work required to stretch a spring 3 ft beyond its natural length is 15 ft-lb, how much work is needed to stretch it 27 in. beyond its natural length?

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