I am a Swedish student, it is the first time I am on Reddit and truthfully I am desperate.
I Got a test in 4 hours and I need to know how to solve these 4 basic questions before I take the test. I have used Google translate.

1. A feather is pulled out 4 cm if you hang 50 grams in it. If the spring is then loaded with a total of 150 grams and can pivot up and down the harmonic motion, which is the period?
   
   
   
2. A mass of 0.5 kg undergoing harmonic motion with a frequency of 2 Hz and an amplitude of 8mm. calculate:
   
   
   
3. A machine produces a certain distance of the sound level 87 decibels, how big would the noise level be if three such machines started simultaneously next to each other?
   
   
   
4. A string has a fundamental frequency of 294 Hz. then press down your finger on the string and it will be 25% shorter. What is the new frequency for the new basic tone that arise?