An ancient club is found that contains 200 g of pure carbon and has an activity of 7.5 decays per second. determine its age assuming that in living trees the ratio of ( 14 c 12 c ) ( 14 c 12 c ) atoms is about 1.10 × 10 − 12 1.10 × 10 − 12 . note that the half life of carbon-14 is 5700 years and the avogadro number is 6.02 × 10 23 6.02 × 10 23 .

An object dropped from cliff falls with a constant acceleration of 10 metre per second square find its speed of two seconds after it was dropped

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

Astronomers studying the planet of rhombus have detected sedimentary rock on its surface. one astronomer wonders if material in this sedimentary rock used to be in igneous rock deep in rhombus’s interior. can igneous rock become sedimentary rock? explain your answer.