what is the magnitude of an electric field in which the electric force on a proton is equal in magnitude to its weight?

What are two different ways you could find the value of a? explain these methods.

Awind turbine is rotating counterclockwise at 0.5 rev/s and slows to a stop in 10 s. its blades are 20 m in length. (a) what is the angular acceleration of the turbine? (b) what is the centripetal acceleration of the tip of the blades at t=0s? (c) what is the magnitude and direction of the total linear acceleration of the tip of the blades at t=0s?

When using the scientist method, which step comes last?