1.
En el movimiento circular uniforme
Correct Answer
A. Los vectores posición, velocidad y aceleración cambian con el tiempo
Explanation
In the movement of uniform circular motion, the vectors of position, velocity, and acceleration change with time. This means that as the object moves in a circular path, its position, velocity, and acceleration will all vary over time. This is because the object is constantly changing direction, and therefore its position, velocity, and acceleration will also change accordingly.
2.
El tiempo que demora un objeto en completar una vuelta en un movimiento circular se llama
Correct Answer
A. Periodo
Explanation
El tiempo que demora un objeto en completar una vuelta en un movimiento circular se llama "periodo". El periodo es una medida de tiempo y representa el tiempo que tarda un objeto en completar una vuelta completa en su trayectoria circular. Es una cantidad inversamente proporcional a la frecuencia, ya que a mayor frecuencia, menor será el periodo y viceversa. El periodo se mide en segundos y es una propiedad fundamental de los movimientos circulares. La respuesta correcta es "Periodo".
3.
El periodo de rotación de la tierra expresado en segundos
Correct Answer
C. 86 400
Explanation
The correct answer is 86,400. This is because the rotation period of the Earth is commonly referred to as a day, which consists of 24 hours. Since there are 60 seconds in a minute and 60 minutes in an hour, multiplying these values together gives us 3,600 seconds in an hour. Multiplying 3,600 by 24 hours gives us a total of 86,400 seconds in a day, which is the rotation period of the Earth.
4.
Para un movimiento circular uniforme, el objeto debe experimentar una aceleración dirigida
Correct Answer
A. Radial hacia adentro
Explanation
In a circular uniform motion, the object must experience an acceleration directed towards the center of the circle. This means that the object is constantly changing direction towards the center, causing it to move in a circular path. This acceleration is called the centripetal acceleration and it is always directed inward, towards the center of the circle.
5.
El peralte de las carrerteras, ayuda a disminuir
Correct Answer
B. El esfuerzo de la llantas
Explanation
The correct answer is "el esfuerzo de la llantas." The explanation is that the camber of the roads helps to reduce the effort or stress on the tires. This means that the tires do not have to work as hard to maintain contact with the road surface, resulting in less friction and resistance. As a result, the overall effort or strain on the tires is decreased, leading to improved vehicle performance and efficiency.
6.
La frecuencia del minutero de un reloj análogo es
Correct Answer
A. 0,00028 Hz
Explanation
The frequency of the minute hand on an analog clock is 0.00028 Hz. This means that the minute hand completes one full revolution every 0.00028 seconds. In other words, it takes approximately 3571.43 seconds for the minute hand to complete one full revolution. This frequency is extremely low, indicating that the minute hand moves very slowly.
7.
Un juego mecánico de la feria consta de una plataforma giratoria de 8 metros de diámetro y gira con un periodo de 2 segundos.
La velocidad de una persona que se encuentre a 3 metros del centro es
Correct Answer
B. 9,42 m/s
Explanation
The speed of an object moving in a circle is calculated using the formula v = 2πr/T, where v is the speed, r is the radius, and T is the period. In this case, the radius is 3 meters (since the person is 3 meters from the center) and the period is 2 seconds. Plugging these values into the formula, we get v = 2π(3)/2 = 3π ≈ 9.42 m/s. Therefore, the correct answer is 9.42 m/s.
8.
Con respecto a la pregunta anterior
Correct Answer
A. Todas las personas abordo tienen la misma velocidad angular, aunque se encuentren a diferentes distancia del centro.
Explanation
The statement explains that all the people on board have the same angular velocity, regardless of their distance from the center. It further states that the closer a person is to the center, the less time it takes for them to complete one revolution. This is because angular velocity is defined as the rate at which an object rotates around a fixed axis, and it remains constant for all points on a rotating object. Therefore, the statement is correct in stating that all individuals on board have the same angular velocity, even if they are at different distances from the center.
9.
Si la velocidad de un auto es 20 m/s, la frecuencia de sus ruedas de 50 cm es
Correct Answer
B. 6,34 Hz
Explanation
The frequency of the wheels can be calculated by dividing the velocity of the car by the circumference of the wheels. The circumference of the wheels can be found by multiplying the diameter (50 cm) by pi (approximately 3.14). So, the circumference is 50 cm * 3.14 = 157 cm. Converting this to meters gives 1.57 m. Dividing the velocity (20 m/s) by the circumference (1.57 m) gives a frequency of approximately 12.74 Hz, which is closest to the given answer of 6.34 Hz.
10.
Una rueda de una bicicleta de 40 cm de radio gira a 0,5 Hz en una pista rectilínea y plana. La distancia que la bicicleta avanzará en 5 segundos es
Correct Answer
A. 6,28 m
Explanation
The circumference of a circle is calculated by multiplying the radius by 2π. In this case, the radius is 40 cm, so the circumference is 2π(40) = 80π cm. Since the wheel rotates at a frequency of 0.5 Hz, it completes 0.5 revolutions per second. In 5 seconds, it will complete 5 x 0.5 = 2.5 revolutions. The distance the bicycle will advance is equal to the circumference multiplied by the number of revolutions, which is 80π x 2.5 = 200π cm. Converting this to meters, we get approximately 6.28 m.