1. Newton's Law of gravitation states (in part) that the force between two masses is

• A. proportional to the square of the distance between them
• B. proportional to the sum of the masses
• C. inversely proportional to the square of the distance between them
• D. inversely proportional to the product of the masses

2. The force between two objects of masS M and m seperated by a distance r is F. If the distance is decreased to r/4 and the mass M increased to 4M, the new force will be

• A. F
• B. 4F
• C. 16F
• D. 64F

3. The gravitational field strength is defined as the

• A. force per unit distance
• B. force per unit mass
• C. acceleration of gravity
• D. accdeleration per unit mass

4. The electric field strength E has units of

• A. NC
• B. NV
• C. NC^-1
• D. NV^-1

5. Which of these diagrams correctly shows the electric field strength between these charges?

6. The gravitational field in the region around the Earth is correctly described as

• A. circular
• B. polar
• C. radial
• D. uniform

7. Two small masses m and 2m are located at distances r and 2r from a much larger planet as shown.

The ratio

is

• A. 2
• B. 1/2
• C. 4
• D. 1/4

8. All three masses in the above diagram will be attracted together. Which mass moves with the largest initital acceleration?

• A. planet
• B. mass m
• C. mass 2m
• D. mass m and 2m have the same acceleration

9. Electric field strength is defined as

• A. the force per unit charge on a small positive test charge
• B. the force per unit charge on a small nagative test charge
• C. the force per unit charge on a unit positive charge
• D. the force per unit charge on a unit negative charge

10. A 2 mC charge is held between two charged plates. The plates have an electric field of 40 kg m s^-1 A^-1 between them. The force on the charge due to the field will be

• A. 20N
• B. 80N
• C. 0.02N
• D. 0.08N