A.từ A về K
T nghĩ vậy chứ ko bt đúng ko :))
True , because gravity is a force of nature. Matter (energy) does attract other matter
Since an alpha particle has 2 protons and no negative particles (electrons) to balance the net charge, its charge is
Q=2(1.6e-19)=3.2e-19C.
The force on a charged particle is F=QE so
(3.2e-19C)(600N/C)=1.92e-16N
Answer:
87.1 mph
Explanation:
We are given that
Mass,m=60 kg
Power,P=340 W
Speed,v=5 m/s
Area,![A=0.344 m^2](https://tex.z-dn.net/?f=A%3D0.344%20m%5E2)
Drag coefficient,![C_d=0.88](https://tex.z-dn.net/?f=C_d%3D0.88)
Coefficient of rolling resistance,![\mu_r=0.007](https://tex.z-dn.net/?f=%5Cmu_r%3D0.007)
Friction force,![f=\mu_rmg=0.007\times 60\times 9.8=4.1 N](https://tex.z-dn.net/?f=f%3D%5Cmu_rmg%3D0.007%5Ctimes%2060%5Ctimes%209.8%3D4.1%20N)
Where ![g=9.8 m/s^2](https://tex.z-dn.net/?f=g%3D9.8%20m%2Fs%5E2)
Let speed of cyclist=v'
Drag force,![F_d=\frac{1}{2}\rho_{air}AC_dv^2](https://tex.z-dn.net/?f=F_d%3D%5Cfrac%7B1%7D%7B2%7D%5Crho_%7Bair%7DAC_dv%5E2)
Density of air,![\rho_{air}=1.225 kg/m^3](https://tex.z-dn.net/?f=%5Crho_%7Bair%7D%3D1.225%20kg%2Fm%5E3)
![F_d=\frac{1}{2}\times 1.225\times 0.344\times 0.88(5)^2=4.635N](https://tex.z-dn.net/?f=F_d%3D%5Cfrac%7B1%7D%7B2%7D%5Ctimes%201.225%5Ctimes%200.344%5Ctimes%200.88%285%29%5E2%3D4.635N)
Power,P=![(F_d+f)\times v'](https://tex.z-dn.net/?f=%28F_d%2Bf%29%5Ctimes%20v%27)
![340=(4.1+4.635) v'=8.735v'](https://tex.z-dn.net/?f=340%3D%284.1%2B4.635%29%20v%27%3D8.735v%27)
![v'=\frac{340}{8.735}=38.9m/s](https://tex.z-dn.net/?f=v%27%3D%5Cfrac%7B340%7D%7B8.735%7D%3D38.9m%2Fs)
![v'=87.1 mph](https://tex.z-dn.net/?f=v%27%3D87.1%20mph)
1 m=0.00062137 miles
1 hour=3600 s
Answer:
Explanation:
The path of waves reaching directly and through reflection from ionosphere will form a isosceles triangle.
Let the height be h . This will be height of a triangle of equal side whose base is of length 32 km. we shall calculate the length of one side of this triangle .
this length be l
l² = 16² + h²
l = √(256 +h² )
2l = 2√(256 +h² )
path difference = 2l - 32 km
For destructive interference
path difference = wavelength /2 for minimum height .
2l - 32 = .344/2
2√(256 +h² )- 32 = . 172
2√(256 +h² ) = 32.172
4(256 +h² ) = 1035
(256 +h² ) = 258.76
h² = 2.76
h = 1.66 km