What is the magnitude of the Electric Field required to suspend an oil drop of mass 1.0 X 10 kg with a charge of 6.2 x 10°C in the Earth's gravitational field?

Which of the following situations is impossible? a) an object has velocity directed east and acceleration directed east. b) an object has zero velocity but non-zero acceleration. c) an object has constant non-zero velocity and changing acceleration. d) an object has velocity directed east and acceleration directed west. e) an object has constant non-zero acceleration and changing velocity.