Answer: beryllium
Explanation: i took the test i got it right!!
Answer:
Frequency is 
Explanation:
Distance between source 1 from the receiver , 
Distance between source 2 from the receiver , 
Now ,
Path difference , 
We know, for constructive interference path difference should be integral multiple of wavelength .
Therefore, 
It is given that n = 1,
Therefore, 
Frequency can be found by , 
Hence, this is the required solution.
Answer:
spring deflection is x = (v2 / R + g) m / 4
Explanation:
We will solve this problem with Newton's second law. Let's analyze the situation the car goes down a road and finds a dip (hollow) that we will assume that it has a circular shape in the lower part has the car weight, elastic force and a centripetal acceleration
Let's write the equations on the Y axis of this description
Fe - W = m 
Where Fe is elastic force, W the weight and
the centripetal acceleration. The elastic force equation is
Fe = - k x
4 (k x) - mg = m v² / R
The four is because there are four springs, R is theradio of dip
We can calculate the deflection (x) of the springs
x = (m v2 / R + mg) / 4
x = (v2 / R + g) m / 4