Asmall mass m is set on the surface of a sphere, the figure. if the coefficient of static friction is 0.75, at what angle ϕ would the mass start sliding?

In order to solve this task you have to match theta as the angle from the top.
Then determine whether force is normal to the sphere, in this case it is normal so: 
After that you need  to appeal to this formula : 

The formula for the force which is  tangential to the sphere :
The last step : the mass starts to slide, 


Hope it has become clear.
Regards.

Iread this book last year so take this with a grain of salt.gene jumps from the tree to compete with finny due to the fact that gene is always trying to do better than finny. he is put under the grasp of peer pressure due to finny almost forcing him to do this. ever since he first jumped finny kept pressuring him to jump since he thought gene enjoyed jumping.rather than uses this answer you should probably just reread chapters 3-4