A train is traveling south at constant speed 12.0 m/s. Then the brakes are applied & it slows down with a constant acceleration to a speed of 3.00 m/s in a time of 9.00 s. (a) Draw a graph of speed versus time for a 12-s interval (starting 2 s before the brakes are applied and ending 1 s after the brakes are released).
(b) What is the acceleration of the train during the 9.00-s interval?
(c) How far does the train travel during the 9.00 s?

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?

Arrange the images in order to show how lake-effect snow occurs.

Place several e-field sensors at a few points on different equipotential lines, and look at the relationship between the electric field and the equipotential lines. which statement is true? 1-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of higher voltages. 2-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of lower voltages. 3-at any point, the electric field is parallel to the equipotential line at that point.