Answer:
One of the more important properties of sound is that its speed is nearly independent of frequency. ... Therefore, the relationship between f and λ is inverse: The higher the frequency, the shorter the wavelength of a sound wave. The speed of sound can change when sound travels from one medium to another.
First body:

Second body:

From description of the task we have:
Given
The y-component of vector K is

The magnitude of vector K is , K=8 cm
To find
The angle

Explanation
Resolving K along its y-component we have,

Conclusion
The angle made with the x-axis is
<span>In real machines, efficiency is always less than 1 .</span>
#82
here we know that
acceleration = 2 m/s/s
time = 5 s
initial speed = 4 m/s
now we can use kinematics to find the final speed



So correct answer will be option D)
#83
here we know that
acceleration = 3 m/s/s
time = 4 s
initial speed = 5 m/s
now we can use kinematics to find the final speed



So correct answer will be option C)
#84
here we know that
acceleration = 7 m/s/s
time = 3 s
initial speed = 8 m/s
now we can use kinematics to find the final speed



So correct answer will be option C)