Answer:
Explanation:
For third normal mode of vibration
l =
, λ is wavelength , l is length of string .
.4 = 
λ = .267 m
velocity = 
T is tension and m is mass unit length
m = .5 x 10⁻³ / 40 x 10⁻²
= .00125 kg / m
Putting the values
velocity = 
= 253 m /s
frequency
= velocity / λ
= 253 / .267
= 947.5 Hz .
Answer:
Plane spacing, 
Explanation:
It is given that,
Wavelength of x-ray, 
Angle the x-ray made with a set of planes in a crystal causing first order constructive interference is 30 degrees
We need to find the plane spacing. It is based on Bragg's law such that,

d is plane spacing
n = 1 here

So, the plane spacing is
.
Answer:
The answer is C.move forward rapidly until stopped.
Explanation:
50 miles an hour is a very high speed. The momentum transfer to the car at stop light will move the car forward rapidly until its brake is able to stop it.
<span>A. The magnetic force increases.
F is inversely proportional to r</span>²<span>
Hope this helps!</span>
Terminal speed is the maximum speed that a falling object can reach and is based on aerodynamic resistance. In a vacuum, an object falling toward a planet as a result of gravity will continue to accelerate until it hits the ground.
However, if the object is falling through an atmosphere, such as on earth, then it will accelerate up to the point that the aerodynamic resistance cancels the downward force due to gravity, and it travels at a constant maximum speed, called the terminal velocity. At this point, resistance is equal to acceleration due to gravity. At terminal velocity, the skydiver's acceleration is zero.