# 16-17.1

### 1. What is the electric field of 34.5 cm to the right of a 12uC charge?

use the formula E = (kq)/(r^2)
E = ((8.99E9)(12E-6))/(.345^2)
E = 906364.209 or 9.06E5 N/C

For questions 2&3 a +13.5uC charge is 88.2 cm to the right of a +23.2uC charge

### 2. What is the force on the leftmost charge? What direction is it?

Use the formula V = (KQ1Q2)/(r^2)
V = ((8.99E9)(23.3E-6)(13.5E-6))/(.882^2)
V = 3.619N to the left

### 3. What is the electric field 32.1cm to the right of the leftmost charge? What direction?

Use the formula: E = (kq/r^2)-(kq/r^2)
E = ((8.99E9)(23.2E-6)/.321^2) - ((8.99E9)(13.5E-6)/.561^2)
E = 1638499.049 or 1.64E6 N/C to the right

### 4. What is the velocity of a proton accelerated through 3.7volts from rest?

Use the formula V = (1/2)mv^2
(3.7)(1.602E-19)=(1/2)(1.673E-27)(V^2)
V^2=7.0779
V = 2.66 m/s

### 5. A 5.2 gram object is suspended against gravity between two horizontal parallel plates that are 5.2cm apart. What charge does the object have if this requires 537V to accomplish? If the top pate is negative, is the charge positive or negative?

Use the formula E = V/X
E = 537/.052
E = 10326.92
Then, use gm=Eq
(9.81)(5.2E-3)=(10326.9)(q)
q = 4.9397E-6