# Physics

A proton is released from rest inside a region of constant, uniform electric field E1 pointing due North. 14.8 seconds after it is released, the electric field instantaneously changes to a constant, uniform electric field E2 pointing due South. 8.07 seconds after the field changes, the proton has returned to its starting point. What is the ratio of the magnitude of E2 to the magnitude of E1? You may neglect the effects of gravity on the proton.

I found that the ratio is just a2/a1. I am not getting the right answer.

1. 👍
2. 👎
3. 👁
1. m = mass of proton
q = charge of proton

During first E1
F = q E1 north
a = q E1/m north
vfinal = (q/m) E1 (14.8)
x final = 0 + 0 +.5 (q/m)E1 (14.8)^2 = (q/m)E1 (110)

Now during E2
x initial = 110 (q/m)E1
Vinitial = (q/m)E1 (14.8)

x final = 0

so
0 = 110(q/m)E1 + 14.8(q/m)E1(8.07)-.5(q/m)E2(8.07^2)
so

.5 E2(8.07)^2 = 110 E1 + 14.8(8.07)E1

32.6 E2 = 110 E1+119 E1 = 229 E1

E2/E1 = 7.04

1. 👍
2. 👎

## Similar Questions

1. ### physics

An electron is released from rest in a uniform electric field and accelerates to the north at a rate of 115 m/s2. What are the magnitude and direction of the electric field.

2. ### physics

A proton moves in a constant electric field E from point A to point B. The magnitude of the electric field is 4.2 x10^4 N/C; and it is directed as shown in the drawing, the direction opposite to the motion of the proton. If the

3. ### physics

A proton is placed in uniform electric field"E" what must be the magnitude and direction of electric field when electrostatic force is balanced by weight

4. ### physics

A Van de Graaff generator is charged so that the magnitude of the electric field at its surface is 2.4 104 N/C. (a) What is the magnitude of the electric force on a proton released at the surface of the generator? (b) Find the

1. ### Physics

An electron is projected with an initial speed of (1.6x10^6 m/s) into the uniform field between two parallel plates. Assume that the field between the plates is uniform and directed vertically downward, and that the field outside

2. ### physics

A proton moves in a constant electric field from point A to point B. The magnitude of the electric field is 6.4 × 10^4 N/C; and it is directed as shown in the drawing, the direction opposite to the motion of the proton. If the

3. ### physics

help me please. *TRUE or FALSE* 1.the north pole of a permanent magnet is attracted to a south pole 2.iron,aluminum, and nickel are all ferromagnetic materials 3.all permanent magnets are surrounded by a magnetic field 4.the

4. ### Physics

A charged particle moves into a region of uniform magnetic field B, goes through half a circle, and then exits that region. The particle is either a proton or an electron (you must decide which). It spends 155 ns in the region. a)

1. ### PHYSICS

please.!PLEASe PLEASE. help me. TRUE or FALSE 1.the north pole of a permanent magnet is attracted to a south pole 2.iron,aluminum, and nickel are all ferromagnetic materials 3.all permanent magnets are surrounded by a magnetic

2. ### Physics

A proton with mass 1.67×10−27 kg and charge 1.60×10−19 C accelerates from rest in a uniform electric field of strength 500 N/C. (a) What is the magnitude of the acceleration of the proton? (b) How long does it take the

3. ### physics!

An electric dipole consists of 2.0 g spheres charged to 5.0 nC (positive and negative) at the ends of a 12 cm long massless rod. The dipole rotates on a frictionless pivot at its center. The dipole is held perpendicular to a

4. ### physics

A proton is released at the origin in a constant electric field of 850 N/C acting in the positive x-direction. Find the change in the electric potential energy associated with the proton after it travels to x = 2.5 m.