A gun is fired 3,681 m away from a mountain. The sound of the shot travels 340m/s. How long will it take for the person who fired the gun to hear the echo? Round to
the nearest whole number.

If two metal balls each have a charge of -10^-6 c and the repulsive force between them is 1 n, how far apart are they? (coulomb's constant is k = 9.0x 10^9 n-m^2/c^2? 9.5 m 9.0 mm 9.5 cm 0.9 m .

Difference between series and parallel circuits

What would be the radius of the earth if it had its actual mass but had the density of nuclei? express your answer to two significant figures and include the appropriate units.