An ambulance is driving towards the hospital at a velocity 108 km/h and emitting a steady 798-Hz sound from its siren. The sound
1 answer:
To solve this problem we will apply the concepts related to the Doppler effect. The Doppler effect is a physical phenomenon where an apparent change in wave frequency is presented by a sound source with respect to its observer when that same source is in motion. Mathematically it can be described as
The meaning of each of these variables is,
Velocity of detector
=Frequency of wave emitted by source
Velocity of source
v=Velocity of sound wave
=Frequency received by detector
Replacing we have that,
Therefore the correct option is e. 950Hz
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Answer: 52 kg skydiver: 9.09 m/s and 522.55 s
95 kg skydiver: 12.3 m/s and 386.2 s
Explanation: <u>Drag</u> <u>Force</u> is an opposite force when an object is moving in a fluid.
For skydivers, when falling through the air, the forces acting on it are gravitational and drag forces. At a certain point, drag force equals gravitational force, which is constant on any part of the planet, producing a net force that is zero. Since there is no net force, there is no acceleration and, consequently, velocity is constant. When that happens, the person reached the <u>Terminal</u> <u>Velocity</u>.
Drag Force and Velocity are proportional to the squared speed. So, terminal velocity is given by:
where
m is mass in kg
g is acceleration due to gravitational force in m/s²
ρ is density of the fluid in kg/m³
C is drag coefficient
A is area of the object in the fluid in m²
Calculating:
The 52kg skydiver has terminal velocity of:
9.09
The 95kg skydiver's terminal velocity is
12.3
The 52 kg and 95kg skydivers' terminal velocity are 9.09m/s and 12.3m/s, respectively.
The time each one will reach the floor will be:
52 kg at 9.09 m/s:
t = 522.5
95 kg at 12.3 m/s:
t = 386.2
The 52 kg and 95kg skydivers' time to reach the floor are 522.5 s and 386.2 s, respectively.
Answer:
v=0.60 m/s
Explanation:
Given that
m ₁= 390 kg ,u ₁= 0.5 m/s
m₂ = 250 kg ,u₂ = 0.76 m/s
As we know that if there is no any external force on the system the total linear momentum of the system will be conserve.
Pi = Pf
m ₁u ₁+m₂u₂ = (m₂ + m ₁ ) v
Now putting the values in the above equation
390 x 0.5 + 250 x 0.76 = (390 + 250 ) v
v=0.60 m/s
Therefore the velocity of the system will be 0.6 m/s.