Answer:
359 m/s
Explanation:
Highest frequency a person can hear is 20,000Hz.
f = c × λ
Frequency = Wave speed × Wavelength
Wavelength = 20,000 ÷ 343 = 58.31m
Wavespeed = Frequency ÷ Wavelength
c = 20,950 ÷ 58.31 = 359.3 m/s
= 359 m/s (3 s.f.)
Strong forces:
- are forces holding nucleons together
- are independent of electric charge
- act only over a very short distance
So, correct answer is 4) all of these
Explanation:
The strong force is one of the 4 fundamental forces of nature. It is responsible for holding the nucleons (protons and neutrons) together into the nucleus of the atom.
In fact, the protons inside the nucleus of an atom experience a repulsive, electrostatic force between each other: if this force was not balanced, the protons will simply fly away from each other, and the nucleus would break apart, so no nucleus could exist.
The strong force acts to prevent this effect: the strong force is attractive at such short scales, and it holds the protons and the neutrons together. It is independent of the electric charge: in fact, it acts in the same way on protons and neutrons, being attractive in both cases. Also, the strong force acts only over very short distances, so it acts only inside the nucleus of an atom.
Therefore, all the statements are correct, so the correct option is
4) all of these
#LearnwithBrainly
Explanation:
work done by friction = 1/2 x 42 x ( 3.33^2 - 11.5^2)
= 21 ( 11.08 - 132.25)
= 21 ( - 121.17 )
= - 2544.57 J
The formula for working out speed is distance ÷ time.
55 km ÷ 2 hours = 27.5 km/h (average speed for first part of journey)
52km ÷ 5 hours = 10.4 km/h (average speed for second part of journey)
(27.5 + 10.4) ÷ 2 = 18.95 km/h (average speed throughout the journey)
"<span>a layer in the earth's stratosphere at an altitude of about 6.2
miles (10 km) containing a high concentration of ozone, which absorbs
most of the ultraviolet radiation reaching the earth from the sun."
Hope this helps!
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