Answer:
30.66 knots
Explanation:
Distance of ship A from B at noon = 50 NM
= Velocity of ship A = 22 knots = 22 NM/h
= Velocity of ship B = 23 knots = 23 NM/h
Distance travelled by ship A from noon to 3 PM = 22×3 = 66 NM
a = Total distance travelled by ship A = 50+66 = 116 NM
b = Total distance travelled by ship B till 3 PM = 23×3 = 69 NM
c = Distance between Ship A and B at 3 PM = √(116²+69²) = 134.97 NM
a²+b² = c² (Pythagoras theorem)
Now differentiating with respect to time

∴ The velocity with which the distance is changing at 3 PM (3 hours later) is 30.66 knots
Answer:
Explanation:
Time needed for a balloon to drop from vertical rest a distance of 11.6 m
t = √(2h/g) = √(2(11.6)/9.8) = 1.538618
d = vt = 4.2(1.538618) = 6.462197...
d = 6.5 m
That tells us that the frequency of the sound wave increased, the period decreased, and the wavelength decreased. The guitar player may be twanging a higher string, OR he may be playing the same note but started walking toward us.