How can friction be when riding a bicycle and how can it be harmful

Now consider the reaction when 45.0 g naoh have been added. what amount of naoh is this, and what amount of fecl3 can be consumed by it?

Naoki's bicycle has a mass of 10 kg. if naoki sits on her bicycle and starts pedaling with a force of 168 n, causing an acceleration of 2.8 m/s2, what is naoki's mass?

Which sample at stp has the same number of atoms as 18 liters of ne at stp