An object having a mass of 25 grams revolves uniformly in a horizontal circle. It is attached by a wire 75 cm long to a pin set in the surface. If the box makes two complete revolutions (1 revolution= .5 seconds) per second, find a) its speed b) tension force exerted on it by the thread i.e. centripetal force. (Convert g to kg and cm to m)
Your teacher is far too easy.
speed=PI(2r)/period. Period is .25 seconds., r is given as .75m
force= mass*speed^2/r