Shown are four arrangements of two unequal positive point charges separated by various distances. Which two arrangements results in the electric potential energy?

Consider two particle mass $m$ and $16m$ separated by a distance $d$.

Deduce that a point $P$, a distance $\frac{d}{5}$ from the particle with mass $m$, the gravitational strength is zero.

The figure shows two oppositely charged parallel plates a distance d apart.

A proton is launched from the negative plate with initial speed u. The proton just reaches the positive plate. Which graph represents the variation of the speed v of the proton with distance x from the negative plate?

An amount of positive charge Q is placed uniformly on a large plane surface. A small positive point charge q placed a perpendicular distance r from the surface experience a force F.

What is the magnitude of the electric field at the position of the small charge q?

A sphere of radius $0.25 \mathrm{m}$ has positive charge $+8.8 \mathrm{\mu C}$ uniformly distributed on its surface. A small pellet of mass $0.075 \mathrm{kg}$ and charge $+2.4 \mathrm{\mu C}$ is directed radially at the sphere. When the pellet is at a distance of 0.75 m from the centre of the sphere its speed is $3.2 \mathrm{m} {\mathrm{s}}^{-1}$.

$\mathrm{a}.$ Determine the distance from the centre of the sphere at which the pellet will stop.

A sphere of radius $0.25 \mathrm{m}$ has positive charge $+8.8 \mathrm{\mu C}$ uniformly distributed on its surface. A small pellet of mass $0.075 \mathrm{kg}$ and charge $+2.4 \mathrm{\mu C}$ is directed radially at the sphere. When the pellet is at a distance of $0.75 \mathrm{m}$ from the centre of the sphere its speed is $3.2 \mathrm{m} {\mathrm{s}}^{-1}$.

$\mathrm{b}.$ Describe qualitatively the subsequent motion of the pellet.

A sphere of radius $0.25 \mathrm{m}$ has positive charge $+8.8 \mathrm{\mu C}$ uniformly distributed on its surface. A small pellet of mass $0.075 \mathrm{kg}$ and charge $+2.4 \mathrm{\mu C}$ is directed radially at the sphere. When the pellet is at a distance of $0.75 \mathrm{m}$ from the centre of the sphere its speed is $3.2 \mathrm{m} {\mathrm{s}}^{-1}$.

$\mathrm{c}.$ Determine the speed of the pellet after it moves very far from the sphere.