The block moves with constant velocity: for Newton's second law, this means that the resultant of the forces acting on the block is zero, because the acceleration is zero.
We are only concerned about the horizontal direction, and there are only two forces acting along this direction: the force F pushing the block and the frictional force
acting against the motion. Since their resultant must be zero, we have:
The frictional force is
where
is the coefficient of kinetic friction
is the weight of the block.
Substituting these values, we find the magnitude of the force F:
In physics, spacetime is any mathematical model which fuses the three dimensions of space and the one dimension of time into a single four-dimensional manifold. Spacetime diagrams can be used to visualize relativistic effects, such as why different observers perceive where and when events occur differently.
The speed of a proton after it accelerates from rest through a potential difference of 350 V is 
.
Initial velocity of the proton 
Given potential difference 
let's assume that the speed of the proton is 
,
Since the proton is accelerating through a potential difference, proton's potential energy will change with time. The potential energy of a particle of charge 
when accelerated with a potential difference 
is,
Due to Work-Energy Theorem and Conservation of Energy - <em>If there is no non-conservative force acting on a particle then loss in Potential energy P.E must be equal to gain in Kinetic Energy K.E</em> i.e
If the initial and final velocity of the proton is 
and respectively then,
change in Kinetic Energy 
change in Potential Energy 
from conservation of energy,
so, 
To read more about the conservation of energy, please go to brainly.com/question/14668053
