Answer:
they are given below
The sum or resultant of all external forces acting on the body must be equal to zero.
The sum or resultant of all external torques from external forces acting on the object must be zero.
Answer: 
Explanation:
The kinetic energy of an electron 
is given by the following equation:
(1)
Where:
is the momentum of the electron
is the mass of the electron
From (1) we can find :
(2)
(3)
Now, in order to find the wavelength of the electron 
with this given kinetic energy (hence momentum), we will use the De Broglie wavelength equation:
(4)
Where:
is the Planck constant
So, we will use the value of found in (3) for equation (4):
(5)
We are told the wavelength of the photon 
is the same as the wavelength of the electron:
(6)
Therefore we will use this wavelength to find the energy of the photon 
using the following equation:
(7)
Where 
is the spped of light in vacuum
Finally:
The faster the job is done, the greater the power
Answer: concave lens
Explanation:
Myopia is a condition of the eye where someone can only see near distant object clearly but not far distant object.
Myopia is corrected using concave lens (diverging) in order to diverge the rays entering the eye thereby allowing the rays to be focused properly on the retina.
