A 0.5 kg mass attached to a string 2 m long is whirled around in a horizontal circle at a speed of 5 m/s. What is the centripetal acceleration of the mass?

Aman is trying to drag a small tree that he cut down. if the static coefficient of friction of the tree on the ground is 0.5 and the tree weighs 670 n, what is the minimum amount of horizontal force that the man will need to apply so that the tree will start moving? o a. 465 n o b. 230 n o c. 670 n o d. 335 n