The wavelength of a wave doubles as it travels
from medium a into medium b. compared to the
wave in medium a, the wave in medium b has
(1) half the speed
(2) twice the speed
(3) half the frequency
(4) twice the frequency

Why there is no inductive reactance in dc circuits

•• 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?

Why does lightning travel from clouds to the ground?