I think it is D
Hope my answer help you?
Answer:
7.39 m or 3.61 m
Explanation:
= Wavelength
f = Frequency = 90 Hz
v = Speed of sound = 340 m/s
Path difference of the two waves is given by

Velocity of wave


So, the location from the worker is 7.39 m or 3.61 m
Answer: mammals may be relatively better at solving problems than birds.
Answer:

Explanation:
Given that,
Heat required, Q = 1200 J
Mass of the object, m = 20 kg
The increase in temperature, 
We need to find the specific heat of the object. The heat required to raise the temperature is given by :

So, the specific heat of the object is
.
Answer:
Coefficient of friction will be 0.587
Explanation:
We have given mass of the car m = 500 kg
Distance s = 18.25 m
Initial velocity of the car u = 14.5 m/sec
As the car finally stops so final velocity v = 0 m/sec
From second equation of motion



We know that acceleration is given by



So coefficient of friction will be 0.587