Physics, 24.07.2020 01:01 varonadestiny1109

A physics professor demonstrates the Doppler effect by tying a 600 Hz sound generator to a 1.0-m-long rope and whirling it around her head in a horizontal circle at 100 rpm. What are the highest and lowest frequencies heard by a student in the classroom

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Answer from: hannahmckain

619.2 Hz and 582.5Hz

Explanation:

Given that

Frequency of the generator, F(s) = 600 Hz

Length if the rope, r = 1 m

Speed of whirling, w = 100 rpm

For starters, we find the speed of the generator, v(g)

v(g) = r.w

It should be noted, however, that we are to convert the speed of whirling from rpm to rad/s, thus

100 rpm = 100 * 2π/60 rad/s

100 rpm = 200π/60

100 rpm = 620.4 / 60

100 rpm = 10.47 rad/s

Now, we use this to find the speed of the generator

v(g) = r.w

v(g) = 1 * 10.47

v(g) = 10.47 m/s

When approaching the generator, the frequency is calculated as

F(a) = F(s) / [1 - (v(g)/v)]

F(a) = 600 / [1 - (10.47/343)]

F(a) = 600 / 0.969

F(a) = 619.2 Hz

On the other hand, the receding generator frequency is

F(r) = F(s) / [1 + (v(g)/v)]

F(r) = 600 / [1 + (10.47/343)]

F(r) = 600 / 1.030

F(r) = 582.5 Hz

Therefore, we can conclude that the highest and lowest frequency is 619.2 Hz and 582.5 Hz respectively

Answer from: Quest

increases it

Answer from: Quest

m₁v₁ + m₂v₂ = (m₁ + m₂)vmomentum is conserved.the left-hand side of the equation represents the momentum in the system before the collision.the right-hand side represents the momentum in the system after the collisionm₁ and v₁ represents the mass and the velocity of the physics blockm₂ and v₂ represents the mass and velocity of the ball of puttyv represents the final velocity of the combined mass.the question states the two masses stick together. they combined mass has its own velocity with the body mass the sum of the two objects' massestheir combined momentum is (m₁ + m₂)vto find the magitude of (m₁ + m₂)v, we need to add the vectors on the left-hand side of the equation: m₁v₁ + m₂v₂.note the diagram. i have positioned the vectors in accordance with their directions.the magnitude of the resultant can be calculated using the pythagorean theorem since this is a right triangle situation (north and west are perpendicular)|(m₁ + m₂)v| = √[ (m₁v₁)² + (m₂v₂)² ]|(m₁ + m₂)v| = √[ (1.5kg·8.0m/s)² + (0.40kg·20m/s)² ]|(m₁ + m₂)v| = 14.4 kg m/sfor two significant figures (assuming that 20m/s is two), this rounds to 14 kg m/s

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A physics professor demonstrates the Doppler effect by tying a 600 Hz sound generator to a 1.0-m-lon...

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