Answer:it is electric current
Explanation:
The frequency produced by the string could be 437 Hz or it could be 443 Hz.
The frequency of the beats ... 3 Hz ... tells the piano tuner that
the difference between the fork and string frequencies is 3 Hz,
but it doesn't tell her which one is higher or lower.
Answer:
The wavelength will be 4 cm, frequency will be 4.66 Hz and wave speed is 18.6 cm/sec
Explanation:
Given:
No. of crest = 13
No. of trough = 15
Time = 3 seconds
Hence, 1 crest or 1 trough = 
therefore,
13 C + 15 T = 
=
Time given 3 seconds
= 

2 cm distance is travelled is time period

Again wave will travel in 1 T = 4 cm
wave speed v =
= 
= 18.6 cm/s
Answer: The correct answer is:
Galileo used instruments and experiments to show him what nature was doing, instead of relying on pure logic
Explanation:
Galileo can be considered as one of the precursors of experimentation and the scientific method. A method that doesn't rely on "common sense" and rationalization and logic, but instead is fuelled by a disposition of skepticism and rather makes claims about reality based on experimentation and empirical data shows.
Galileo differed from his predecessors because he actually used and developed instruments and method to reliable measure and observe what nature was doing, instead of relying on pure logic.