7. A student in a lab exerts a 30 N force to pull a block a distance of 36 cm. If a total of 10 J of work is done, a. 890 the angle between the force and the displacement is b. 220 d. 240 C. 380 e. none of the above 8. A 100-g sparrow flying at 17.1 m/s wishes to have equal kinetic and gravitational potential energies. The height that will accomplish this is a. 0.15 m b. 1.5 m d. 150 m c. 15.00 m e. 1500 m 9. Earth's mass is 5.98 x 1024 kg. Calculate the value of g at a point 7.2 x 10 km from the centre of Earth. a. 9.8 x 10-2 N/kg d. 1.7 x 103 N/kg b. 7.6 x 10' N/kg e. 5.8 x 105 N/kg c. 1.7 x 10 3 N/kg 10. A piece of paper becomes electrically charged when a charged rod of plastic is placed close to it. This is referred to as a. charging by a conductor d. charging by contact b. charging by electricity e. charging by induction c. charging by an insulator + 20 cm 20 cm 1 1. Four charged spheres, K, D, P, and V are arranged as shown below. Sphere K has a charge of +4.5x10 C, sphere D has a charge of -6.2x 10"C, sphere P has a charge of +7.5x10" C, and sphere V has a charge of -1.5x10 C. Which two spheres exert the smallest force on each other? a. K and D d. P and D b. K and P P and V C. K and V