Answer:
64.945 miles per hour
Explanation:
Since the frequency of sound heard is higher than actual frequency, the ambulance is moving towards you!
The frequency of sound waves as heard from a distance for a sound wave coming towards one at v₀ m/s and whose real frequency is f₀ is given by
+f = f₀/[1 - (v₀/v)]
+f = frequency of sound as heard from the distance away = 8.61 KHz
f₀ = real frequency of sound = 7.87 KHz
v₀ = velocity at which the sound source is moving towards the reference point = ?
v = velocity of sound waves = 343 m/s
8.61 = 7.87/(1 - (v₀/v))
1 - (v₀/343) = 0.9141
v₀/343 = 1 - 0.9141 = 0.0859
v₀ = 343 × 0.0859 = 29.48 m/s = 64.945 miles per hour
I think it may be c i learned about this last year
<span>If the swimmer is swimming perpendicular to the current, it will take her 66m / 0.42 m/s = 157.14 seconds to cross the river. At the same time, the current will be taking her downstream at a rate of 0.32 m/s. So, when she reaches the opposite bank, her total downstream distance traveled will have been 0.32*157.14 = 50.28 meters.</span>
Answer:
largest lead = 3 m
Explanation:
Basically, this problem is about what is the largest possible distance anchorman for team B can have over the anchorman for team A when the final leg started that anchorman for team A won the race. This show that anchorman for team A must have higher velocity than anchorman for team B to won the race as at the starting of final leg team B runner leads the team A runner.
So, first we need to calculate the velocities of both the anchorman
given data:
Distance = d = 100 m
Time arrival for A = 9.8 s
Time arrival for B = 10.1 s
Velocity of anchorman A = D / Time arrival for A
=100/ 9.8 = 10.2 m/s
Velocity of anchorman B = D / Time arrival for B
=100/10.1 = 9.9 m/s
As speed of anchorman A is greater than anchorman B. So, anchorman A complete the race first than anchorman B. So, anchorman B covered lower distance than anchorman A. So to calculate the covered distance during time 9.8 s for B runner, we use
d = vt
= 9.9 x 9.8 = 97 m
So, during the same time interval, anchorman A covered 100 m distance which is greater than anchorman B distance which is 97 m.
largest lead = 100 - 97 = 3 m
So if his lead no more than 3 m anchorman A win the race.
