Answer:
33.6371 m
Explanation:
t = Time taken
u = Initial velocity = 20.3 m/s
v = Final velocity
s = Displacement
a = Acceleration = -7 m/s²
Distance traveled in the 0.207 seconds
Distance = Speed × Time
⇒Distance = 20.3×0.207 = 4.2021 m
Equation of motion
Distance traveled by the car while braking is 29.435 m
Total distance measured from the point where the driver first notices the red light is 29.435+4.2021 = 33.6371 m
Answer:
Explanation:
Since work done is in the form of potential energy, we will use the formula of potential energy here.
We know that,
<h3>P.E. = mgh </h3>Where,
m = mass = 20 kg
g = acceleration due to gravity = 10 m/s²
h = vertical height = 20 m
So,
<h3>Work done = mgh</h3>Work done = (20)(10)(20)
Work done = 4000 joules
Work done = 4 kJ
Answer:
4.6 kHz
Explanation:
The formula for the Doppler effect allows us to find the frequency of the reflected wave:
where
f is the original frequency of the sound
v is the speed of sound
vs is the speed of the wave source
In this problem, we have
f = 41.2 kHz
v = 330 m/s
vs = 33.0 m/s
Therefore, if we substitute in the equation we find the frequency of the reflected wave:
And the frequency of the beats is equal to the difference between the frequency of the reflected wave and the original frequency: