Answer:
Well I'm going to go with A.
Explanation:
As per the question the mass of the boy is 40 kg.
The boy sits on a chair.
We are asked to calculate the force exerted by the boy on the chair at sea level.
The force exerted by boy on the chair while sitting on it is nothing else except the force of gravity of earth i.e the weight of the body .The direction of that force is vertically downward.
At sea level the acceleration due to gravity g = 9.8 m/s^2
Therefore, the weight of the boy [m is the mass of the body]
we have m = 40 kg.
Therefore, w = 40 kg ×9.8 m/s^2
=392 N kg m/s^2
= 392 N
392 is not an option but I'm guessing you can round down 2 .to option A. 390...?
The magnitude of the change in potential energy is equal to the kinetic energy,
or
Here, V is potential difference, q is charge, m is mass and v is velocity.
We can also write,
Given 
Substituting this value with mass of proton, 
and charge of proton,
we get
Therefore, the speed of proton is 
.
A) True there able to target the people they post the assignment on.
<span />
