A 24 {rm g}, 3-cm-diameter thin, hollow sphere rotates at 30rpm about a vertical, frictionless axis throughout its center. A 4g bug stands at the top of the sphere. He then walks along surface of the sphere until he reaches its “equator.” 30 {rm rpm} about a vertical, frictionless axis through its center. A 4 {rm g} bug stands at the top of the sphere. He then walks along the surface of the sphere until he reaches its “equator.”

When he reaches the equator, the sphere is rotating at how many rpm?

Question2

A boat heading due north crosses a 168-m wide river with the speed of 10.0 km/h relative to the water. 
The water in river has a uniform speed of 5.00 km/h and flows due East. 

(a) What is velocity of the boat relative to the shore?

(b) How long does it take a boat to cross the river? 

(c) How for downstream does a boat end up?