The question is not complete
Answer:
-3.396 m/s or 3.465 m/s
Explanation:
v = Speed of sound in air = 343 m/s
= Relative speed of the singer
f = Observed frequency
f' = Actual frequency
1% change can mean 
From the Doppler effect equation we have
The velocity is -3.396 m/s
when 
The velocity is 3.465 m/s
The kinetic energy is 945 joules.
Kinetic energy is the energy that an object has as a result of motion. It is defined as the effort required to accelerate a mass-determined body from rest to the indicated velocity.
The speed of an object or particle, which is a scalar quantity, is the size of the change in its location over time or the size of the change in its position per unit of time.
The mass of the volleyball is 2.1 kg.
The speed of the ball when the ball leaves the hand is 30 m/s.
m = 2.1 kg
v = 30 m/s
The kinetic energy of an object is given as:
KE = (1/2 ) × m × v²
KE = (1 / 2) × 2.1 kg × ( 30 m/s)²
KE = (1 / 2) × 2.1 kg × 30 m/s × 30 m/s
KE = 2.1 kg × 15 m/s × 30 m/s
KE = 945 J
Learn more about kinetic energy here:
brainly.com/question/8101588
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