Answer:
False
Explanation:
All the lanthanides are not radioactive in nature. Just one of the lanthanides are radioactive.
- The lanthanides belong to the f-block on the periodic table
- Only Promethium in this group are radioactive in nature.
- Other elements in the lanthanide series might have radioactive isotopes.
Then the force of gravity between them would be quadrupled and so on but the gravitational force is inversely proportional to the square of the separation distance between the two interacting objects which makes more separation distance will result in weaker gravitational forces
To be honest I’m not really sure cause I’m in 5th grade but the red planet is the sun
1. True
2. True
3. True
4. True
5. 10ft
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