A 2.0 g ball with a +0.05 C charge is moved from the negative plate to the positive plate, then released. The potential difference between the plates is 12.0V. When the ball strikes the (–) plate its velocity is most nearly equal to: a. 6 m/s
b. 12 m/s
c. 17 m/s
d. 25 m/s

25 m/s

Explanation:

The ball will have kinetic energy that is proportional to the energy due to the product of the charge and the potential difference.

mass of the ball m = 2.0 g = 2 x kg

charge on the ball C = +0.05 C

potential difference on plates V = 12.0 V

The energy due to the electric potential difference and the charge will be

E = CV

E = 0.05 X 12 = 0.6 Joules

The ball will move with a kinetic energy that is proportional to this energy calculated (due to energy conservation principle), therefore,

E = ..........which is the kinetic energy relationship where v is the velocity of the ball, substituting values in, we have

0.6 = x 2 x x

0.6 = x

600 =

v = = 24.49 ≅ 25 m/s

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.

the higher the current the higher the mag field around it the higher the influence on the compass