Quiz 14:

1. Which of the following is true about gravitational force between two objects.

• A. It is proportional to the square of the distance separating them.
• B. It is inversely proportional to the square of the distance separating them.
• C. It is inversely proportional to the distance separating them.
• D. It is inversely proportional to the cube of the distance separating them
• E. It is proportional to the distance separating them.

2. By how much would the gravitational force between two objects be multiplied if the mass of one of the objects is multiplied by a factor of 2 and the mass of the other object is multiplied by a factor of 7?

• A. 3.5
• B. 9
• C. 14
• D. 0.286
• E. 0.071

3. Object 1 and Object 2 are located on the x-axis at x = 1500 m and x = 400 m respectively. What is the direction of the gravitational force exerted by object 1 on object 2?

• A. It can not be determined
• B. East
• C. South
• D. North
• E. West

4. An object of mass 3000 kg and an object of mass 9000 kg are separated by a distance of 1000 m. Calculate the gravitational force exerted by one on the other.

• A. 0.353e-9 N
• B. 1.277e-9 N
• C. 0.958e-9 N
• D. 1.801e-9 N
• E. 0.7e-9 N

5. A satelite of mass 400000 kg is revolving around earth at an altitude of 4000 km above the surface of earth. Earth has a mass of 5.98e24 kg and a radius of 6.38e6 m. Calculate the acceleration with which the satelite is revolving around earth.

• A. 1.464 m ⁄ s²
• B. 4.72 m ⁄ s²
• C. 5.717 m ⁄ s ²
• D. 6.18 m ⁄ s ²
• E. 3.702 m ⁄ s²

6. A car of mass 2900 kg is turning on a curve of radius of curvature 60 m. The coeffient of friction between the tires of the car and the ground is 0.25. Calculate the centripetal force that keeps it in the circular path.

• A. 3498.112 N
• B. 8362.461 N
• C. 7105 N
• D. 2613.191 N
• E. 12518.423 N

7. An object of mass 0.25 kg is revolving in a circular path of radius 0.15 m on a friction less table by means of a string which is attached to a hanging object of mass 1.5 kg (the string is attached to the hanging object through a hole on the table at the center of the circular path). Calculate the speed with which the object on the table is revolving on the circular path.

• A. 2.621 m ⁄ s
• B. 3.981 m ⁄ s
• C. 2.188 m ⁄ s
• D. 2.97 m ⁄ s
• E. 0.689 m ⁄ s

8. A 2 kg pendulum of length 0.8 m that makes an angle of 40 deg with the vertical is revolving in a horizontal circle. Calculate the speed with which it is revolving on the horizontal circle.

• A. 2.056 m ⁄ s
• B. 0.832 m ⁄ s
• C. 3.499 m ⁄ s
• D. 1.568 m ⁄ s
• E. 3.121 m ⁄ s

9. An object of mass 4 kg is revolving in a vertical circle of radius 1.3 m. Calculate the minimum speed at the top of the circle by which the object can make it without the string slacking.

• A. 3.029 m ⁄ s
• B. 3.569 m ⁄ s
• C. 5.854 m ⁄ s
• D. 6.423 m ⁄ s
• E. 0.88 m ⁄ s

10. An object of mass 3 kg is revolving in a vertical circle of radius 1.7 m. If its speed at the top of the circle is the minimum speed by which it can make it without the string slacking, calculate its speed at the bottom of the circle.

• A. 11.132 m ⁄ s
• B. 9.127 m ⁄ s
• C. 8.002 m ⁄ s
• D. 15.717 m ⁄ s
• E. 4.925 m ⁄ s