Cousin Throckmorton is playing with the clothesline. One end of the clothesline is attached to a vertical post. Throcky holds the other end loosely in his hand, so that the speed of waves on the clothesline is a relatively slow 0.700 m/s . He finds several frequencies at which he can oscillate his end of the clothesline so that a light clothespin 40.0 cm from the post doesn't move. What are these frequencies?

The  frequencies are  

Explanation:

From the question we are told that

   The speed of the wave is  

   The  length of vibrating  clothesline is  

Generally the fundamental frequency is  mathematically represented as

=>    

=>    

Now  this other frequencies of vibration experience by the clotheslines are know as harmonics and they are obtained by integer multiple of  the fundamental frequency

So  

   The  frequencies are mathematically represented as

=>    

Where  n  =  1, 2, 3 ....

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.