A water droplet of radius 0.018 mm remains stationary inthe air. If the downward-directed electric field of the Earthis 150 N/C, how many excess electron charges must thewater droplet have?

Physics 211, Week 10 Notes PSU: Fall term Chapter 11: Rolling Bodies: For a wheel of radius R rolling smoothly Vcom = wR Where Vcom is the linear speed of the wheel’s center of mass and w is the angular speed of the wheel about its center. The wheel may also be viewed as rotating instantaneously about the point P of the “road” that is in contact with the wheel. The angular speed of the wheel about this point is the same as the angular speed of the wheel about its center. The rolling wheel has kinetic energy If the wheel is being accelerated but is still rolling smoothly, the acceleration of the center of mass is related to the angular acceleration about the center with-> If the wheel rolls smoothly down