7. Astudert in a lab exerts a 25 N force to pull a block a distance of48 cm. Ifatotal of 1 1 J of work is done, the angle between the force and the displacement is a, 890 b. 66 c. 61° A 102-g sparrow flying at 12.3 m/s wishes to have equal kinetic and gravitational potential energies. The height that will accomplish this is a. 0.315 m b. 0.628 m c. 0.787 m ? d. 24 e. none of the above S. d. 1.13 m e. 7.72 m Earth\'s mass is 5.98 x 10* kg. Calculate the value of g at a point 4.8 x 10 km from the centre of Earth. a. 9.8 x 10 N/kg b. 8.3 x 10 N/kg c. 1.7 x 10 N/kg 9. d. 1.7 x 10 N/kg e. 9.8x 10 Nkg 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 b. charging by induction c. charging by an insulator 10. d. e. charging by contact charging by electricity 20 cm 20 em C, 11 . Four charged spheres, A, D, P, and T are arranged as shown below. Sphere A has a charge of +4.5x 10 sphere D has a charge of-6.2x 10 Csphere Phas a charge of 7.5x 10 C, and sphere T has a charge of -1.5x 101C. Which two spheres exert the smallesr force on each other? a. A and D b. A and T c. A and F P and D P and T d. e. 3 of 13 Solution 7. W = F * d * cos x; where x is the angle between force and displacement W = 11J, d = 0.48m, F = 25N solving for cos x = 11/(25*0.48) = 0.91 x= arc cos (0.91) ~ 89 degrees - (a) 8. 0.5* m * v^2 = m*g*h cancelling out m h = 0.5 * v^2/g = 0.5*12.3^2 / 9.81 = 7.72 m - (e) .

1. 7. Astudert in a lab exerts a 25 N force to pull a block a distance of48 cm. Ifatotal of 1 1 J of
work is done, the angle between the force and the displacement is a, 890 b. 66 c. 61° A 102-g
sparrow flying at 12.3 m/s wishes to have equal kinetic and gravitational potential energies. The
height that will accomplish this is a. 0.315 m b. 0.628 m c. 0.787 m ? d. 24 e. none of the above
S. d. 1.13 m e. 7.72 m Earth's mass is 5.98 x 10* kg. Calculate the value of g at a point 4.8 x 10
km from the centre of Earth. a. 9.8 x 10 N/kg b. 8.3 x 10 N/kg c. 1.7 x 10 N/kg 9. d. 1.7 x 10
N/kg e. 9.8x 10 Nkg 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 b. charging by induction c.
charging by an insulator 10. d. e. charging by contact charging by electricity 20 cm 20 em C, 11 .
Four charged spheres, A, D, P, and T are arranged as shown below. Sphere A has a charge of
+4.5x 10 sphere D has a charge of-6.2x 10 Csphere Phas a charge of 7.5x 10 C, and sphere T has
a charge of -1.5x 101C. Which two spheres exert the smallesr force on each other? a. A and D b.
A and T c. A and F P and D P and T d. e. 3 of 13
Solution
7.
W = F * d * cos x; where x is the angle between force and displacement
W = 11J, d = 0.48m, F = 25N
solving for cos x = 11/(25*0.48) = 0.91
x= arc cos (0.91) ~ 89 degrees - (a)
8. 0.5* m * v^2 = m*g*h
cancelling out m
h = 0.5 * v^2/g
= 0.5*12.3^2 / 9.81 = 7.72 m - (e)