Answer:
The correct answer is d
Explanation:
In this exercise they ask us which statement is correct, for this we plan the solution of the problem, this is a Doppler effect problem, it is the frequency change due to the relative speed between the emitter and the receiver of sound.
The expression for the Doppler effect of a moving source is
f ’= (v / (v- + v_s) f
From this expression we see that if the speed the sound source is different from zero feels a change in the frequency.
The correct answer is d
If the box is moving at constant velocity, net force must be zero, so:
F + fr = 0
fr = -F
<u>fr = -40 N</u>
Potential energy decreases and kinetic energy increases.
Potential energy is related to the height, since the wagon is going downhill, height decreases and potential energy decreases.
Kinetic energy is related to the speed, since the wagon is speeding up, kinetic energy increases.
The displacement of the object as determined from the velocity-time graph is 562.5 m.
<h3>What is a velocity-time graph?</h3>
A velocity-time graph is a graph of the velocity of an object plotted in the vertical or y-axis of the graph against the time taken on the horizontal or x-axis.
The displacement of an object can be obtained from its velocity-time graph by calculating the total area under the graph.
The total area under the graph = area of triangle + area of rectangle
Area of triangle = b*h/2 =
Area of triangle = 25 * (35 - 10)/2 = 312.5 m
Area of rectangle = l * b
Area of rectangle = 10 * 25 = 250 m
Total area = (312.5 + 250) m
Total area = 562.5 m
Therefore, the displacement of the object is 562.5 m
In conclusion, the total area of a velocity-time graph gives the displacement.
Learn more about velocity-time graph at: brainly.com/question/28064297
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