Answer:
31.2 m/s
Explanation:
= Frequency of approach = 480 Hz
= Frequency of going away = 400 Hz
= Speed of sound in air = 343 m/s
= Speed of truck
Frequency of approach is given as
eq-1
Frequency of moving awayy is given as
eq-2
Dividing eq-1 by eq-2
= 31.2 m/s
Answer: Yes.
Explanation: Because of the crystalline structure.
B it’s the most logical answer
Answer:B)439.21 Hz
Explanation:
Given
velocity of train 
frequency of train 
speed of sound 
frequency from Doppler effect can be calculated by
Answer:
Both balls will hit the ground at the same time
Explanation:
The factor which leads to ball falling is the gravity acting on the ball;
The motions along the path of both balls are independent and both balls will obey the following illustration
Using the third equation of motion
s = ut + ½at²
Where s = distance covered by both balls.
u = initial velocity of both balls. Since both balls start from rest, u = 0m/s
a = acceleration; and it's equal to acceleration due to gravity.
a = g
By substituton
s = 0 * t + ½gt²
s = 0 + ½gt²
s = ½gt²
Make t the subject of formula
gt² = 2s
t² = 2s/g
t = ±√(2s/g)
But time can't be less than 0 (in other words, negative)
So,
t = √(2s/g)
It'll take both balls √(2s/g) time to hit the floor
