A 16.2 - Vector Field

Get the assessment: FA16.2.docx

Get the Practice Problems: Worksheet-ProblemsFromA16.2.docx

The Assessment solved:

1. A uniform electrical field exerts a force of 0.890 N to the left on a -410. µC charge. What is the change in electrical potential if you move 2.60 m to the left? Is it an increase in potential, or a decrease?

(5640 V, increase)

2. If you move a mass vertically from point A to point B in a uniform gravitational field, the potential changes from -12.0 J/kg to +23.0 J/kg in a distance of 17.0 m. What force does the field exert on a 5.20 kg mass, and which point is at a higher elevation, A or B? Does the field point toward A or B?

(10.7 N, B is higher, toward A)

More like this: (pretty important to look at these - it is two questions on this SA)

(From Practice 1-10 below)

3. What is the electric field 34.5 cm above a -12.0 mC charge?

(9.06x105 N/C down)

(Like Practice 11-20 below)

4. Find the gravitational field at p and at point q:

(p: 9.32 N/kg left, q: 5.91 N/kg left)

More Practice Problems:

Problems from A16.2 Vector Fields: (Assume all these fields are uniform)

1. A gravitational field increases the potential of a mass from 35.0 J/kg at point A to 89.0 J/kg at point B in a vertical distance of 2.50 m. What is the field strength, and what force does it exert on a 23.0 kg mass? Does the field point toward B or A? (21.6 N/kg, 497 N, toward A)

P16.2#1

2. An electric field exerts a Southerly force of 1.30 N on a +780. µC charge. What is the change in potential if you displace yourself 5.30 m to the north? (+8830 V)

P16.2#2

3. A gravitational field exerts a force of 140. N on a 17.0 kg mass away from point B and toward point A that is vertically displaced from B a distance of 45.0 m. What is the field strength? What is the change in gravitational potential if you go from B to A? (8.24 N/kg, -371 J/kg)

P16 2#3

4. An upward electric field has a strength of 23,400 N/C. What is the change in potential if you displace yourself upward 3.40 cm? What force will it exert on an electron? A proton? (-796 J/C or V, 3.75x10-15 N down, 3.75x10-15 N up)

P16 2#4

5. If you move 12.0 m West in an electrical field, your electrical potential drops by 340. V. What is this electrical field? What force does this field exert on a charge of -56.0 µC? (28.3 V/m (or N/C) to the West, 1.59x10-3 N East)

P16.2#5

6. A gravitational field has a strength of 1.10x10-7 N/kg to the right. If I move a mass 2.30 m to the left, what is the change in gravitational potential? What force does this exert on a 1.00 gram object?

(+2.53x10-7 J/kg, 1.10x10-10 N)

P16 2#6

7. An electrical field changes electrical potential from 210. V to 560. V when you move down 4.50 cm. What is the magnitude and direction of the electrical field, and what force does it exert on a +2.40 µC charge? (7780 V/m (or N/C) up, 0.0187 N up)

P16 2#7

8. An electrical field exerts a force of 78.0 N to the left on a -12.0 µC charge. What is the magnitude and direction of this electrical field? What is the change in electrical potential if you move 13.0 cm to the left? (6.50x106 N/C right, +8.45x105 V)

9. The leftmost of two vertical parallel plates is held at -12.0 V, and the rightmost is held at +16.0 V. If they are separated by 3.20 cm, what is the electrical field between them? What force would it exert on an electron between the plates? (875 V/m to the left, 1.40x10-16 N to the right)

10. If you move a mass vertically from point A to point B, the potential changes from -45.0 J/kg to -12.0 J/kg in a distance of 3.40 m. What is the gravitational field strength, and which point is at a higher elevation, A or B? Does the field point toward A or B? (g = 9.71 N/kg toward A, B is higher)

11. The electric field is 52.0 N/C downwards 54.0 cm above a charge. What is the charge, and is it positive or negative? (-1.69x10-9 C, negative)

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12. What is the electric field 230. m above a +21.0 µC charge? What direction is it? (3.57 N/C up)

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13. Near a -18.0 mC charge there is an upward electric field of 450. N/C. How far away is the point where this happens, and where is it, above or below the charge? (19.0 m, below)

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14. There is an electric field of 310. N/C upwards 88.0 cm above an unknown charge. What is the charge, and is it positive or negative? (2.67x10-8 C, positive)

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15. What is the electric field 2.70 m to the left of a +8.20 mC charge? What direction is it? (1.01x104 N/C, left)

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16. At what distance from the center of a 6.90x1024 kg planet is the gravitational field 4.50 N/kg? (1.01x107 m)

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17. What is the acceleration of gravity on the surface of a planet with a mass of 6.39x1023 kg and a radius of 3.39x106 m? (Mars) (3.71 N/kg)

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18. What is the gravitational field 4.50 m to the right of a 2.80x1012 kg point mass? What direction? (9.22 N/kg left)

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19. Near a 3.40x1012 kg point mass there is a field of 5.60 N/kg to the left. What distance are we from the point mass, and where is the mass in relation to us? (6.36 m, the mass is to our left)

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20. There is a gravitational field of 14.0 N/kg to the right, 7.20 m from a point mass. What is the mass, and where are we in relation to the mass? (1.09x1013 kg, we are to the left of the mass)

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21.

A. Find the gravitational field at p and q: (p: 8.29 N/kg left, q: 8.23 N/kg left)