Answer:
the average force exerted by seatbelts on the passenger is 5625 N.
Explanation:
Given;
initial velocity of the car, u = 50 m/s
distance traveled by the car, s = 20 m
final velocity of the after coming to rest, v = 0
mass of the passenger, m = 90 kg
Determine the acceleration of the car as it hit the pile of dirt;
v² = u² + 2as
0 = 50² + (2 x 20)a
0 = 2500 + 40a
40a = -2500
a = -2500/40
a = -62.5 m/s²
The deceleration of the car is 62.5 m/s²
The force exerted on the passenger by the backward action of the car is calculated as follows;
F = ma
F = 90 x 62.5
F = 5625 N
Therefore, the average force exerted by seatbelts on the passenger is 5625 N.
Burning of paper is the answer
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:
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