Please Help No Link Seriously

Astone dropped into a well is heard to strike the water after 8seconds. find the depth of the well if the velocity of sound is 350m/s

Wavelength,frequency,and energy are related.what happens to a wave as it’s wavelength gets shorter?

What is the electric force acting between two charges of -0.0045 c and -0.0025 c that are 0.0060 m apart? use fe=kq1q2/r^2 and k = 9.00 x 10^9 n*m^2/c^2 a. 1.7 x 10^7 n b. -1.7 x 10^7 n c. -2.8 x 10^9 n d. 2.8 x 10^9 n