Doppler effect is the phenomenon in which there is an increase or decrease in the frequency when there is relative motion between the source and listener.

Pitch depends on the frequency. if the frequency increases then pitch increases.

When the source and the listener are moving towards each other then there is increase in the frequency. When the source and the listener are moving away each other then there is decrease in the frequency.

In the given problem, Juan is standing on the street. An ambulance moves toward him and then passes by the pitch drops to a lower pitch once the ambulance passes by Juan.

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3 years ago

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What is the force required to produce a 1.4 Nm torque when applied to a door at a 60.0º angle and 0.40 m from the hinge?

Marysya12 [62]

Refer to the diagram shown below.

The component of the applied force perpendicular to the door is
F * sin(60°) = 0.866F N

Because the moment arm is 0.40 m, the torque is
(0.866F N)*(0.4 m) = 0.3464F N-m

This torque is equal to 1.4 N-m, therefore
0.3464F = 1.4
F = 4.04 N

Answer: 4.04 N

5 0

3 years ago