An alpha particle (α), which is the same as a helium-4 nucleus, is momentarily at rest in a region of space occupied by an electric field. The particle then begins to move. Find the speed of the alpha particle after it has moved through a potential difference of â3.45Ã10^â3 V .The charge and the mass of an alpha particle are qα = 3.20Ã10^â19 C and mα = 6.68Ã10â27 kg , respectively. Mechanical energy is conserved in the presence of which of the following types of forces?

a. electrostatic
b. frictional
c. magnetic
d. gravitational

Speed = 575 m/s

Mechanical energy is conserved in electrostatic, magnetic and gravitational forces.

Explanation:

Given :

Potential difference, U =

Mass of the alpha particle,

Charge of the alpha particle is,

So the potential difference for the alpha particle when it is accelerated through the potential difference is

And the kinetic energy gained by the alpha particle is

From the law of conservation of energy, we get

The mechanical energy is conserved in the presence of the following conservative forces :

-- electrostatic forces

-- magnetic forces

-- gravitational forces

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.