Usually nice weather , i dont know the answer to the second part
Can you translate to english ?
Answer:
The higher the frequency, the shorter the wavelength. Because all light waves move through a vacuum at the same speed, the number of wave crests passing by a given point in one second depends on the wavelength. Speed shows how long it takes for wavelengths to travel.
Answer:
S1 = 1/2 g t^2 distance stone falls in time t
S2 = Vy t - 1/2 g t^2 distance thrown stone rises in time t
H = 49 = S1 + S2 = Vy t
t = 49 / 40 sec time when stones meet
Check:
Stone 1 falls: 1/2 g t^2 = 1/2 * 9.8 * (49 / 40)^2 = 7.35 m
Stone 2 rises : 40 * (49 / 40) - 1/2 * 9.8 (49 / 40)^2 = 41.65 m