Un capacitor de placas paralelas separadas por aire, de 5.8 μF, tiene una separacion de 5 mm y esta cargado a una diferencia de potencial de 400 V .
(a) Calcule la energia potencial y densidad de energıa almacenada entre las placas.
(b) Si se inserta un dielectrico con K = 2.7 entre las placas del capacitor, cual es ahora la energıa potencial
y densidad de energıa almacenada?.

•• al and bert are jogging side-by-side on a trail in the woods at a speed of 0.75 m/s. suddenly al sees the end of the trail 35 m ahead and decides to speed up to reach it. he accelerates at a constant rate of 0.50 m/s2, while bert continues on at a constant speed. (a) how long does it take al to reach the end of the trail? (b) once he reaches the end of the trail, he immediately turns around and heads back along the trail with a constant speed of 0.85 m/s. how long does it take him to meet up with bert? (c) how far are they from the end of the trail when they meet?

True or false: the revolution of the earth creates day and night as it rotates around the sun

Astudent is performing an experiment comparing sound and light waves. the student gathers the following data. what conclusion does the student most likely make based on this data? light waves always travel the same speed; however, the speed of sound is determined by the medium that it travels through. all sound waves always have the same energy, so the temperature of the medium does not affect wave speed. light needs to vibrate particles, so it travels fastest in tightly packed solids, while sound does not need a medium, so it travels fastest in a gas. tightly packed particles in solids slow down the light waves; however, sound waves make particles bounce into each other, so they travel faster in solids.