A proton is traveling horizontally to the right at $4.50\(\times\)10^6$ m/s. What minimum field (magnitude and direction) would be needed to stop an electron under the conditions of part (a)? Note: Part (a) asks for how much time does it take the proton to stop after entering the field.

A uniform electric field exists in the region between two oppositely charged plane parallel plates. A proton is released from rest at the surface of the positively charged plate and strikes the surface of the opposite plate, $1.60$ cm distant from the first, in a time interval of $3.20\(\times\)10^{-6}$ s. Find the speed of the proton when it strikes the negatively charged plate.

A proton is traveling horizontally to the right at $4.50\(\times\)10^6$ m/s. How much time does it take the proton to stop after entering the field?

A proton is traveling horizontally to the right at $4.50\times {10}^6$ m/s. Find the magnitude and direction of the weakest electric field that can bring the proton uniformly to rest over a distance of $3.20$ cm.

A $-4.00$-nC point charge is at the origin, and a second $-5.00$-nC point charge is on the $x$-axis at $x=0.800$ m. Find the electric field (magnitude and direction) at each of the following points on the $x$-axis: (i) $x=0.200$ m; (ii) $x=1.20$ m; (iii) $x=-0.200$ m.

A $+8.75$-mC point charge is glued down on a horizontal frictionless table. It is tied to a $-6.50$-mC point charge by a light, nonconducting $2.50$-cm wire. A uniform electric field of magnitude $1.85\(\times\)10^8$ $N/C$ is directed parallel to the wire, as shown in Fig. E$21.34$. What would the tension be if both charges were negative?

A $+8.75$-mC point charge is glued down on a horizontal frictionless table. It is tied to a $-6.50$-mC point charge by a light, nonconducting $2.50$-cm wire. A uniform electric field of magnitude $1.85\times {10}^8$ $N/C$ is directed parallel to the wire, as shown in Fig. E$21.34$. Find the tension in the wire.