Answer:
The first harmonic is: 250Hz, second harmonic 500Hz, third harmonic 750Hz.
Explanation:
Use the frequency f, speed v, and wavelentgh L relationship:
We are given the speed v=400 m/s. The base wavelength on a string of length 80cm is twice the length of the string (a "half wave" along the full length of the string), so:
The fundamental frequency (first harmonic) is 250 Hz
The second harmonic is produced by one full wave across the string (adding one node in the middle), so L=80cm in this case, therefore the second harmonic frequency is: f2 = 2*250=500Hz
the third harmonic add another node (and a half wave) to the pattern and the wavelength will be 2/3 of 80cm, so f3=3*250Hz = 750Hz
Answer:
Her computer is producing thermal energy, not heat.
Explanation:
It can be used to separate two objects or portions of an object, lift up an object, or hold an object in place.
Answer:
(a) Work done by the tension force is 987 J
(b) Coefficient of kinetic friction between the crate and surface is 0.495
Explanation:
(a)
Work done by any force F in moving an object by a distance d making an angle 
with the direction of force is given by
Thus work done by the tension force is 987 J
(b)
Normal force on the crate is given by
=>N=332 Newtons
Since crate is moving with constant speed . Therefore using Newtons second law .
Where 
=coefficient of kinetic friction
=>
=>
Thus coefficient of kinetic friction between the crate and surface is 0.495
