Una pelota rueda por una pendiente con aceleración constante. Cuando pasa por un punto P su velocidad es 1,2 ms-1 y al cabo de un breve periodo de tiempo pasa por el punto Q con una velocidad de 2,6 ms-1 . a. Determine ¿cuál es la velocidad media entre P y Q?
b. Si tarda 1,4s en ir de P a Q, calcule ¿cuál es la distancia PQ?
c. Determine ¿cuál es la aceleración de la pelota entre P y Q?
d. Explicar si la aceleración media en el tramo P y Q es la misma que la calculada en la pregunta c

An ideal polarizer with its transmission axis rotated 30 degrees to the vertical is placed in a beam of unpolarized light of intensity 10w/m^2. after passing through the polarizer, what is the intensity of the beam? a. 8.7 w/m^2 b. 7.5 w/m^2 c. 5.0 w/m^2 d. 10 w/m^2 e. 2.5 w/m^2

Clothing made of several thin layers of fabric with trapped air in between, often called ski clothing, is commonly used in cold climates because it is light, fashionable, and a very effective thermal insulator. so it is no surprise that such clothing has largely replaced thickand heavy old-fashioned coats. (a) consider a jacket made of five layers of 0.1-mm-thick synthetic fabric (k = 0.13 w/m·°c) with 1.5-mm-thick air space (k = 0.026 w/m·°c) between the layers. assuming the inner surface temperature of the jacket to be 28°c and the surface area to be 1.25 m2, determine the rate of heat loss through the jacket when the temperature of the outdoors is 0°c and the heat transfer coefficient at the outer surface is 25 w/m2·°c. (b) what would your response be if the jacket is made of a single layer of 0.5-mm-thick synthetic fabric? what should be the thickness of a wool fabric (k = 0.035 w/m·°c) if the person is to achieve the same level of thermal comfort wearing a thick wool coat instead of a five-layer ski jacket?

Acertain radio station broadcasts radio waves that have a wavelength of 298cm what is its broadcast frequency?