A current in a river flows downstream at a speed of 2 m/s. A swimmer can swin with a speed of 0.5 m/s with respect to the water. The swimmer heads directly across the stream, and crosses the stream in a time of 30 seconds. How wide is the stream?

Aprotein molecule in an electrophoresis gel has a negative charge. the exact charge depends on the ph of the solution, but 30 excess electrons is typical. what is the magnitude of the electric force on a protein with this charge in a 1600n/c electric field? write in two significant numbers, and also in newton