Answer: 529.9 Hz
Explanation:
Here we need to use the Doppler equation, so we have:
f' = f*(v + v0)/(v - vs)
Here, f is the frequency = 500Hz
v is the velocity of the wave, = 334m/s
v0 is the velocity of the observer = 20m/s
vs is the velocity of the source = 0m/s
Then we have:
f' = 500Hz*(334m/s + 20m/s)/(334m/s) = 529.9 Hz
Answer:

Explanation:
From the question we are told that
Mass 
Height 
Generally the equation for velocity before impact is is is mathematically given by



Generally the equation for Kinetic Energy is is mathematically given by




Answer:
acceleration = v-u /t
30- 20/5
= 10/5 = 2m/sec²
Force = mass * acceleration
Force = 0.1 * 2
Force = 0.2 Newton
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