What is one way to induce an electric current

What should the power status of a circuit be when measuring resistance with an ohmmeter?

Your target variable is δf, the magnitude of the difference in frequency between the waves emitted from the sonar device and the waves received by the device after reflecting off the whale. write an expression for δf in terms of the relevant frequencies using the subscript notation introduced above.

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration