Answer:
Reflection of sound waves also leads to echoes. Echoes are different than reverberations. Echoes occur when a reflected sound wave reaches the ear more than 0.1 seconds after the original sound wave was heard. ... Reflection of sound waves off of curved surfaces leads to a more interesting phenomenon.
Answer:
0.5sec
Explanation:
Parameters
Height(H) =20m
Initial velocity(u) = 5m/s
Acceleration due to gravity(g) =10m/s^2
Method one
Using the second law of motion
H=ut-1/2gt^2
20=5t-1/2×10×t^2
20=5t-5t^2
dh/dt = 5-10t
where any constant is zero therefore the 20 is zero
5-10t=0
Collect like terms
-10t= -5
t=1/2 = 0.5sec
2nd method
Parameters
Height(H) =20m
Initial velocity(u) = 5m/s
Acceleration due to gravity(g) =10m/s^2
Using the time taken formula
t=u/g
t=5/10
t=0.5sec
I don't know what you meant 'dontk'.
