Free Law of Universal Gravitation MCQs with Answers

11. The value of acceleration due to gravity on moon is _ of earth.

• A. 1/4th
• B. 1/10th
• C. 2/3rd
• D. 1/6th

Explanation: This is a fact to be memorized. Gravitational acceleration on Moon is 1/6th the gravitational acceleration on Earth. Hence Option D is correct.

12. Acceleration due to gravity near earth is:

• A. Non uniform
• B. Uniform
• C. Decreasing with distance
• D. Increasing with time

Explanation: The acceleration due to gravity near Earth is approximately uniform. On Earth's surface, the standard acceleration due to gravity, denoted as "g," is approximately 9.81 meters per second squared (m/s²) and is relatively constant at a given location. This means that the acceleration due to gravity remains nearly the same for objects in the vicinity of Earth's surface, regardless of their mass. However, it's worth noting that the value of "g" can vary slightly depending on your location on Earth and other factors like altitude and local geology. For example, it is slightly higher at the poles and decreases slightly as you move toward the equator due to Earth's rotation and shape. Nevertheless, these variations are relatively small, and for most practical purposes, we consider the acceleration due to gravity as uniform near Earth's surface.

13. On the ground, the gravitational force on a satellite is W. What is the gravitational force on the satellite when at a height R/50, where R is the radius of the Earth?

• A. 1.04 W
• B. 1.02 W
• C. 0.98 W
• D. 0.96 W
• E. 2.13 W

Explanation: Because of equality F = - m. (G.M/r ²) = - m.g one draws G = G.M/r ² = [G.M/R ²] * [1 (1+z/R)]² =g○/(1+z/R) ² ► g (z) = g○/(1+z/R) ² ▬▬▬▬▬ > W/W○ = g/g○ = (1+z/R)⁻ ² = (1 + 1/50)^-2 = 0.961