Answer: Experimenting to determine the fundamental properties of x-rays.
Explanation:
Scientific basic research aims to find the fundaments or principles of the phenomena.
The basic research is intended to understand the matter, its nature, its properties, its behavior. It searches to make theory. To finding how the things work but not how to use those things for a determined purpose.
The study of the properties of the atom to understand what it is, how it interacts with other atoms, how it determines the properties of the matter are some examples of basic research, such as experimenting to determine the fundamental properties of x-rays is.
On the other hand, the other examples given, Spencer's research on WWII radar technology that led to the invention of the microwave oven, Edison's research and use of other scientists' work to invent the light bulb, and Morrison and Franscioni's research done to create the Frisbee, are examples of applied research science. This is research to find a valuable use of some scientific knowledge.
Given data
*The given 4th harmonic frequency is 31.5 Hz
The fundamental frequency is calculated as

Hence, the fundamental frequency is 7.875 Hz
Complete Question
Suppose you hit a steel nail with a 0.500-kg hammer, initially moving at 15.0 m/s and brought to rest in 2.80 mm. How much is the nail compressed if it is 2.50 mm in diameter and 6.00-cm long.What Average force is excreted on the Nail
Answer:

Explanation:
From the question we are told that:
Mass 
Initial Velocity 
Distance 
Diameter 
Length 
Generally the equation for Force is mathematically given by



The answer is A. speed
hope this helps! :D