Question

In determining Newtons equations using a n,t,b concordant system why do we not consider acceleration in either direction a force? Example posted below.

Answer 1

We consider both components with accelerations whereby

for x-component, which is called centripetal acceleration therefore centripetal force.

for y-component, since it is static, therefore a=0

Hope this helps

Answer 2

Not sure if I understand, we consider the normal force and the force due to gravity (unless friction is introduced) but not acceleration or velocity. From the picture illustrated the force in the "n" direction is \[N _{c}\sin()\] and not \[N _{c} Sin(\theta)\pm a_{n}\]

If we were to consider the magnatude, what would we call that value? i.e. \[\sqrt{a _{n}^{2}+a _{t}^{2} }\]