a vibrating source with a frequency of 20.0Hz produces water waves that have a wavelength of 3.0 cm. Calculate the speed of the waves 

Astudent throws a water balloon with speed v0 from a height h = 1.76 m at an angle θ = 21° above the horizontal toward a target on the ground. the target is located a horizontal distance d = 9.5 m from the student’s feet. assume that the balloon moves without air resistance. use a cartesian coordinate system with the origin at the balloon's initial position. (a) what is the position vector, rtarge t, that originates from the balloon's original position and terminates at the target? put this in terms of h and d, and represent it as a vector using i and j. (b) in terms of the variables in the problem, determine the time, t, after the launch it takes the balloon to reach the target. your answer should not include h. (c) create an expression for the balloon's vertical position as a function of time, y(t), in terms of t, vo, g, and θ. (d) determine the magnitude of the balloon's initial velocity, v0, in meters per second, by eliminating t from the previous two expressions.

If an electric circuit is not grounded it is best to reach out and touch it to provide the ground a.true or b.false

To fully describe the photoelectric effect, scientists must consider which of the following to be quantized? o a. both light and matter o b. matter only o c. light only o d. neither light nor matter