A police car with its 300-Hz siren is moving toward a warehouse at 30 m/s, intending to crash through the door. The sound bounce
1 answer:
Answer: The frequency heard will be f = 275.675Hz
Explanation: When an object emitting sound is moving, it occurs a phenomenon called Doppler shift or Doppler effect. What happens is that the sound gets higher when the moving object comes closer the observer and becomes lower after it passes, This change is due to the quantity of waves that passes through an area in an unit of time.
The formula to calculate the Doppler effect is as follows
f = () · f₀
f is the observed frequency;
c is the speed of sound;
Vs is velocity of the source;
f₀ is the emitted frequency of source;
Substituting and calculating,
f = · 300
f = 275.675 Hz
Thus, the frequency heard by the police officer is 275.675Hz.
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Answer:
a) = 4.67m/s
b) V = 8.29 m/s
Explanation:
Givens:
The bullet is 5.30g moving at 963m/s and its speed reduced to 426m/s. The wooden block is 610g.
a) From conservation of linear momentum
Pi = Pf
where are the mass and the initial velocity of the bullet,
and
are the mass and the initial velocity of the wooden block, and
and
are the final velocities of the wooden block and the bullet
The wooden block is initial at rest this yields
By solving for adn substitute the givens
=
=
= 4.67m/s
b) The center of mass speed is defined as
substituting:
V = 8.29 m/s