Two automobiles are equipped with the same single-frequency horn. When one is at rest and the other is moving toward the first at 20 m/sm/s , the driver at rest hears a beat frequency of 5.2 HzHz .

The frequency of the horn is 83.87 Hz

Explanation:

Given:

v = speed of the second horn = 20 m/s

vs = speed of the sound = 343 m/s

Δf = beat frequency = 5.2 Hz

The apparent frequency is equal to:

The frequency of the horn is equal:

convex lenses are thicker at the middle. rays of light that pass through the lens are brought closer together (they converge). a convex lens is a converging lens. when parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.

the bal will not change its velocity.