Answer:
pressure= force/area
A solid resting on a horizontal surfaceexerts a normal contactforce equals to its weight. The pressure of the solid on the surface depends on the area of contact. (b) the area of contact between the two surfaces. The greater the force or the smaller the area the greater the pressure.
The atomic number of an atom says how many protons it has. This number cant change, since the atomic number is what gives elements their identities (in the periodic table, at least).
The mass number, on the other hand, says how many protons AND neutrons the atom has (so, the sum of P+ and N0). So, electrons have nothing to do with this number.
Atoms are neutrally charged, which means there has to be an equal number of positive and negative particles. The negative particles of an atom are its electrons, and since our atom has 4 protons, it must also have 4 electrons.
Explanation:
v = wavelength x frequency
330 = 5 . 10-² m x f
f = 6600 Hz
the frequency that human can hear is about 20 Hz - 20000 Hz
so human can hear the note.
Answer:
C.) Gravity
Explanation:
The projectile is an object upon which the only force is gravity. Gravity acts to influence the vertical motion of the projectile.
If the period of a satellite is T=24 h = 86400 s that means it is in geostationary orbit around Earth. That means that the force of gravity Fg and the centripetal force Fcp are equal:
Fg=Fcp
m*g=m*(v²/R),
where m is mass, v is the velocity of the satelite and R is the height of the satellite and g=G*(M/r²), where G=6.67*10^-11 m³ kg⁻¹ s⁻², M is the mass of the Earth and r is the distance from the satellite.
Masses cancel out and we have:
G*(M/r²)=v²/R, R=r so:
G*(M/r)=v²
r=G*(M/v²), since v=ωr it means v²=ω²r² and we plug it in,
r=G*(M/ω²r²),
r³=G*(M/ω²), ω=2π/T, it means ω²=4π²/T² and we plug that in:
r³=G*(M/(4π²/T²)), and finally we take the third root to get r:
r=∛{(G*M*T²)/(4π²)}=4.226*10^7 m= 42 260 km which is the height of a geostationary satellite.