Answer:
The second trumpeter will be playing at frequency = 515 Hz
Explanation: Given that the note sounds lower and they can hear 20 beats in 4.0 s.
Beat frequency = 20/4 = 5 Hz
Beat frequency = F2 - F1
5 = 520 - F1
F1 = 520 - 5
F1 = 515 Hz
Since the note sound lower, the second trumpeter will be playing at 515 Hz frequency
To solve this problem it is necessary to apply the concepts related to the Centrifugal Force and the Gravitational Force. Since there is balance on the body these two Forces will be equal, mathematically they can be expressed as


Where,
m = Mass
G =Gravitational Universal Constant
M = Mass of the Planet
r = Distance/Radius
Re-arrange to find the velocity we have,

At the same time we know that the period is equivalent in terms of the linear velocity to,


If our values are that the radius of mars is 3400 km and the distance above the planet is 100km more, i.e, 3500km we have,



Replacing we have,



Therefore the correct answer is C.
Answer:
so initial speed of the rock is 30.32 m/s
correct answer is b. 30.3 m/s
Explanation:
given data
h = 15.0m
v = 25m/s
weight of the rock m = 3.00N
solution
we use here work-energy theorem that is express as here
work = change in the kinetic energy ..............................1
so it can be written as
work = force × distance ...................2
and
KE is express as
K.E = 0.5 × m × v²
and it can be written as
F × d = 0.5 × m × (vf)² - (vi)² ......................3
here
m is mass and vi and vf is initial and final velocity
F = mg = m (-9.8) , d = 15 m and v{f} = 25 m/s
so put value in equation 3 we get
m (-9.8) × 15 = 0.5 × m × (25)² - (vi)²
solve it we get
(vi)² = 919
vi = 30.32 m/s
so initial speed of the rock is 30.32 m/s
If you know an element’s atomic number, you will learn the number of protons and electrons. The atomic number is equal to the number or protons and electrons. You can also find the number of neutrons, by subtracting the atomic mass from the atomic number.
For example, Fluorine’s atomic number is 9, and its atomic mass is 19. So, the number of electrons and protons in fluorine is 9. The number of neutrons the is equal to 19-9. Thus, Fluorine has 10 neutrons.
Hope this helps :)