28 is balanced and unbalanced
Answer:

Explanation:
From the question we are told that:
Beat frequency 
Frequency 
Generally the equation for Frequency of the violin is mathematically given by



Therefore the period of the violin string oscillations is



Answer:
A) continue to move to the right, with its speed increasing with time.
Explanation:
As long as force is positive , even when it is decreasing , it will create positive increase in velocity . Hence the body will keep moving with increasing velocity towards the right . The moment the force becomes zero on continuously decreasing , the increase in velocity stops and the body will be moving with the last velocity uniformly towards right . When the force acting on it becomes negative , even then the body will keep on going to the right till negative force makes its velocity zero . D uring this period , the body will keep moving towards right with decreasing velocity .
Hence in the present case A , is the right choice.
The answer is believed to be C because the evidence is from fossils and glaciers.
When a layer of cold air close to the ground is covered by a layer of warmer air, sound waves traveling upward may be bent, or refracted, by the difference in temperature and redirected toward the ground.