Centripetal acceleration and tangential acceleration?

A door in a hospital has a pneumatic closer that pulls the door shut such that the doorknob moves with contant speed over most of its path. In this part of its motion: a) Does the doorknob experience a centripetal acceleration? b) Does it experience a tangential acceleration? Hurrying to an emergency, a nurse... show more A door in a hospital has a pneumatic closer that pulls the door shut such that the doorknob moves with contant speed over most of its path. In this part of its motion:
a) Does the doorknob experience a centripetal acceleration?
b) Does it experience a tangential acceleration?

Hurrying to an emergency, a nurse gives the door a sharp push to the closed door. The door swings open against the pneumatic device, slowing down and then reversing its motion. At the moment the door is open the widest:

c) does the doorknob have a centripetal acceleration?
d)Does it have a tangential acceleration?
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