Which animal have no teeth

Karen is running forward at a speed of 9 m/s. she tosses her sweaty headband backward at a speed of 20 m/s. the speed of the headband, to the nearest whole number relative to a stationary observer watching karen

Apulley with mass mp and a radius rp is attached to the ceiling, in a gravity field of 9.81 m/s2 and rotates with no friction about its pivot.

Why does lightning travel from clouds to the ground?