Answer:
12N
Explanation:
when a force is applied to a body but still stays at rest or moves at a constant speed , the frictional force is equal to the force applied
Answer: What is this supposed to be converted into?
Explanation:
Answer:
The energy of photon, 
Explanation:
It is given that,
Voltage of anode, 
We need to find the maximum energy of the photon of the x- ray radiation. The energy required to raise an electron through one volt is called electron volt.

e is charge of electron


So, the maximum energy of the x- ray radiation is
. Hence, this is the required solution.
1) The total mechanical energy of the rock is:

where U is the gravitational potential energy and K the kinetic energy.
Initially, the kinetic energy is zero (because the rock starts from rest, so its speed is zero), and the total mechanical energy of the rock is just gravitational potential energy. This is equal to

where

is the mass,

is the gravitational acceleration and

is the height.
Putting the numbers in, we find the potential energy

2) Just before hitting the ground, the potential energy U is zero (because now h=0), and all the potential energy of the rock converted into kinetic energy, which is equal to:

where v is the speed of the rock just before hitting the ground. Since the mechanical energy of the rock must be conserved, then the kinetic energy K before hitting the ground must be equal to the initial potential energy U of the rock:

3) For the work-energy theorem, the work W done by the gravitational force on the rock is equal to the variation of kinetic energy of the rock, which is:
Answer:
2.345 would be the most precious because you have more numbers to work with and exact numbers