Humans can typically perceive frequencies that range from 20 hz–20 khz. dogs can hear sounds up to 45 khz. dog whistles produce sound waves that range from 23–54 khz; therefore, they cannot be heard by the human ear. which statement accurately describes the pitch and wavelength of the sound waves produced by a dog whistle? high pitch with a long wavelength high pitch with a short wavelength low pitch with a short wavelength low pitch with a long wavelength

Which of the following changes will result in a stronger electromagnet? a. using fewer coils of wire b. using a higher voltage c. using a shorter nail d. using a longer wire

An charge with mass m and charge q is emitted from the origin, (x,y)=(0,0). a large, flat screen is located at x=l. there is a target on the screen at y position y(h), where y(h) > 0. in this problem, you will examine two different ways that the charge might hit the target. ignore gravity in this problem. 1.assume that the charge is emitted with velocity v(0) in the positive x direction. between the origin and the screen, the charge travels through a constant electric field pointing in the positive y direction. what should the magnitude e of the electric field be if the charge is to hit the target on the screen? express your answer in terms of m, q, y(h), v(0), and l. 2.now assume that the charge is emitted with velocity v(0) in the positive y direction. between the origin and the screen, the charge travels through a constant electric field pointing in the positive x direction. what should the magnitude e of the electric field be if the charge is to hit the target on the screen? express your answer in terms of m, q, y(h), v(0), and l.

Write a hypothesis about the effect of increasing resistance on the current in the circuit. use theformat and be sure to answer the lesson question. “how do changes in voltage or resistance affect current in an electric circuit? ”