How many electrons have been removed from a positively charged electroscope if it has a net charge of 1.6× 10−13 C?

A6.0-kilogram cart initially traveling at 4.0 meters per second east accelerates uniformly at 0.50 meter per second squared east for 3.0 seconds. what is the speed of the cart at the end of this 3.0 second interval? (1) 1.5 m/s (3) 3.0 m/s (2) 5.5 m/s (4) 7.0 m/s