Solve practice problem 1,3,6,7

Practice Understanding Concepts Answer 1. Two charged spheres, 10.0 cm apart, attract each other with a force of magni- 1. (8) 1.2 X 10-5 N tude 3.0 x 10" N. What force results from each of the following changes, con- sidered separately? (a) Both charges are doubled, while the distance remains the same. 330 Chapter 7 NEL CS CamScanner Google Docs Section 7.2 12 2 (b) An uncharged, identical sphere is touched to one of the spheres and is then taken far away. Answers (c) The separation is increased to 30.0 cm. 1. (b) 1.5 x 10-6 N 2. The magnitude of the force of electrostatic repulsion between two small posi- (c) 3.3 x 10 7 N tively charged objects, A and B, is 3.6 x 10-5 N when / = 0.12 m. Find the force 2. (a) 9.0 x 10- N of repulsion if ris increased to (a) 0.24 m, (b) 0.30 m, and (c) 0.36 m. (b) 5.8 X 10- N 3. Calculate the force between charges of 5.0 x 10-8 C and 1.0 x 10-7C if they (c) 4.0 X 10-6 N are 5.0 cm apart. 3. 1.8 x 10-2 N . Calculate the magnitude of the force a 1.5 x 10- C charge exerts on a 3.2 x 10- C charge located 1.5 m away. 4. 1.9 N 5. 1.0 x 10-" C: 2.0 x 10-" C 5. Two oppositely charged spheres, with a centre-to-centre separation of 4.0 cm, attract each other with a force of magnitude 1.2 x 10-9 N. The magnitude of the 6. 0.51 m charge on one sphere is twice the magnitude of the charge on the other. 7. 37 * 10 70 1.2 .107C Determine the magnitude of the charge on each. 6. Two equal uniform spherical charges, each of magnitude 1.1 x 10-7 C, experi- ence an electrostatic force of magnitude 4.2 x 10-4 N. How far apart are the centres of the two charges 7. Two identical small spheres of mass 2.0 g are fasteried to the ends of an insulating thread of length 0.60 m. The spheres are suspended by a hook in the ceiling from the centre of the thread. The spheres are given identical electric charges and hang in static equilibrium, with an angle of 30.0" between the string halves, as shown in Figure 5. Calculate the magnitude of the charge on each sphere. 30.0