Answer:
Option D. 4.4 m/s²
Explanation:
The following data were obtained from the question:
Velocity (v) = 21 m/s
Radius (r) = 100 m
Centripetal acceleration (a) =.?
The centripetal acceleration of the car can be obtained as follow:
Centripetal acceleration (a) = Velocity square (v²) / radius (r)
a = v²/r
a = 21²/100
a = 441/100
a = 4.41 ≈ 4.4 m/s²
Therefore, the centripetal acceleration of the car is 4.4 m/s².
A 1 complete revolution corresponds to an angular displacement of 2π rad, or 360º. (So there are 180º for every π rad.) Also, there are 60 seconds to 1 minute. So, the angular velocity in rad/s is
(2000 rev/min) * (2π rad/rev) * (1/60 min/s) = 200π/3 rad/s
or approximately 209.44 rad/s.
B First convert the angular velocity to degrees per second (º/s):
(200π/3 rad/s) * (180/π º/rad) = 12,000 º/s
We want to find the time <em>t</em> it would take for the propeller to turn 36º:
36º = (12,000 º/s) <em>t</em>
==> <em>t</em> = 36º / (12,000 º/s) = 3/1000 s
or approximately 0.003 s.
<u>Answer</u>
Increasing frequency
<u>Explanation</u>
When the source of sound and the observer are moving towards each other the frequency tends to be increasing. Since wavelength is inversely proportional to the frequency, the wave decreases when the frequency increases.
These effect is called the Doppler effect named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842
The van's AVERAGE speed up the hill is
1/2 (20+12) m/s
= 1/2 (32 m/s)
= 16 m/s.
Traveling for 8 seconds at an average speed of 16 m/s, the van covered
(16 m/s) • (8 sec) = 128 meters .
