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stiks02
7 days ago
6

Rosa studies the position-time graph of two race cars. A graph titled Position versus Time shows time in hours on the x axis, nu

mbered 0 to 5, position in kilometers on the y axis, numbered 0 to 50. The graph has two straight lines, one from point (0, 20) up to (2.8, 50), the second line starts at the origin and goes to point (5, 20). Rosa concludes that truck X has a greater velocity than truck Y, and that truck Y had a head start. She also concluded that the graph shows both trucks moving at a constant velocity and that neither truck changes direction. Which statement best describes Rosa’s error?
A Both trucks change direction after they start moving.
B Truck X had a head start, not truck Y.
C Truck Y has a greater velocity than truck X.
D The trucks are not traveling at constant velocities.
Physics
2 answers:
Sav [1K]7 days ago
5 0

Answer:

B. Truck X was ahead, not truck Y.

Explanation:

Let's analyze the information provided.

Truck X moved from the point (0,20) to (2.8,50). This indicates that it began at the 20th kilometer and reached 50 km in 2.8 hours. Thus, its speed is v1 = (s2 - s1) / t

v1 = (50 - 20) / 2.8

v1 = 10.7 km/h

Given that it started from the 20th km, it indeed had a head start. Since the line on the graph is linear, this shows its speed was constant without any change in direction.

On the other hand, Truck Y's movement went from the origin (0,0) to (5,20), meaning it took 5 hours to travel 20 km, resulting in a speed of v2 = 20 / 5

v2 = 4 km/h

Again, the straightness of its graph line signifies it maintained a constant speed in a single direction.

Thus, it is evident that Rosa erred in her assumption that Truck Y had a head start.

Maru [1K]7 days ago
4 0

Answer:

The correct answer is C

Explanation:

I just completed the test and answered it correctly

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Answer:

a)n= 3.125 x 10^{19 electrones.

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c)V_{d =1.114 x 10^{4m/s

d) ver explicación

Explanation:

La corriente 'I' = 5A =>5C/s

diámetro 'd'= 2.05 x 10^{-3 m

radio 'r' = d/2 => 1.025 x 10^{-3 m

número de electrones 'n'= 8.5 x 10^{28}

a) La cantidad de electrones que pasan por la bombilla cada segundo se determina mediante:

I= Q/t

Q= I x t => 5 x 1

Q= 5C

Como sabemos que: Q= ne

donde e es la carga del electrón, es decir, 1.6 x 10^{-19C

n= Q/e => 5/ 1.6 x 10^{-19

n= 3.125 x 10^{19 electrones.

b) La densidad de corriente 'J' en el cable se calcula como

J= I/A => I/πr²

J= 5 / (3.14 x (1.025x 10^{-3)²)

J= 1.515 x 10^{6 A/m²

c) La velocidad típica 'V_{d' de un electrón se expresa como:

V_{d = \frac{J}{n|q|}

    =1.515 x 10^{6 / 8.5 x 10^{28} x |-1.6 x 10^{-19|

V_{d =1.114 x 10^{4m/s

d) De acuerdo con estas ecuaciones,

J= I/A

V_{d = \frac{J}{n|q|} =\frac{I}{nA|q|}

Si utilizaras un cable de doble diámetro, ¿cuáles de las respuestas anteriores cambiarían? ¿Aumentarían o disminuirían?

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5 days ago
If the coefficient of static friction between a table and a uniform massive rope is μs, what fraction of the rope can hang over
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13 days ago
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Para calcular el peso utilizamos la fórmula:
F=m*g=882N

Cuando tenemos dos cuerpos, empleamos la fórmula de la gravedad general:
F=G* \frac{ M_{p}*M_{E} }{ r^{2} }
Donde:
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m*g=G* \frac{ M_{p}*M_{E} }{ r^{2} }

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1 day ago
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