Answer: The force constant k is 10600 kg/s^2
Step by step: 
Use the law of energy conservation. When the elevator hits the spring, it has a certain kinetic and a potential energy. When the elevator reaches the point of still stand the kinetic and potential energies have been transformed to work performed by the elevator in the form of friction (brake clamp) and loading the spring. 
Let us define the vertical height axis as having two points: h=2m at the point of elevator hitting the spring, and h=0m at the point of stopping. 
The total energy at the point h=2m is:

The total energy at the point h=0m is:

The two Energy values are to be equal (by law of energy conservation), which allows us to determine the only unknown, namely the force constant k:

 
        
             
        
        
        
Answer:
1. the electromagnetic wave.
Explanation:
Mathematically, 
wavelength = velocity ÷ frequency
A mechanical wave is a wave that is not capable of transmitting its energy through a vacuum. Mechanical waves require a medium in order to transport their energy from one location to another. A sound wave is an example of a mechanical wave. Sound waves are incapable of traveling through a vacuum.
Electromagnetic waves of different frequency are called by different names since they have different sources and effects on matter, increasing frequency decreases wavelength.
Sound waves (which obviously travel at the speed of sound) are much slower than electromagnetic waves (which travel at the speed of light.)  
Electromagnetic waves are much faster than sound waves and If the Velocity of the wave increases and the frequency is constant, the wavelength also increases.
 
        
             
        
        
        
<h2>
Answer: A</h2>
Explanation because the distance covered is equal time intervals is the same or equal.