Tina speaks using a nonelectric megaphone. The megaphone makes her voice louder in one direction. How does a megaphone work?
Select one:

It affects the vocal cords of a person and allows them to make louder sounds.

It increases the amplitude of spreading sound waves.

It changes the frequency of the spreading sound waves.

It collects sound waves and reflects them in a direction.

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.

Athin nonconducting rod with a uniform distribution of positive charge q is bent into a circle of radius r. the central perpendicular axis through the ring is a z-axis, with the origin at the center of the ring. a) what is the magnitude of the electric field due to the rod at z = 0? n/c (b) what is the magnitude of the electric field due to the rod at z = infinity? n/c (c) in terms of r, at what positive value of z is that magnitude maximum? r (d) if r = 4.00 cm and q = 9.00 µc, what is the maximum magnitude? n/c