Practice Gravity in Physics
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
The universal attractive force between any two objects with mass, decreasing with the square of distance.
Everything pulls on everything else—but only huge things (like Earth) pull noticeably.
Example 1
easyCalculate the gravitational force between Earth (M = 5.97 \times 10^{24} \text{ kg}) and a 1 \text{ kg} object at Earth's surface (r = 6.37 \times 10^6 \text{ m}). Use G = 6.674 \times 10^{-11} \text{ N m}^2/\text{kg}^2.
Example 2
mediumAt what height above Earth's surface would the gravitational acceleration be half of g? Earth's radius is R = 6.37 \times 10^6 \text{ m}.
Example 3
easyA ball is dropped from rest near Earth's surface. How fast is it going after 3 \text{ seconds}? Ignore air resistance and use g = 9.8 \text{ m/s}^2.
Example 4
mediumCalculate the gravitational force between two 50 \text{ kg} masses separated by 2 \text{ m}. Use G = 6.674 \times 10^{-11} \text{ N m}^2/\text{kg}^2.
Example 5
mediumWhat gravitational force exists between two 5 \text{ kg} masses whose centers are 2 \text{ m} apart? Use G = 6.674 \times 10^{-11} \text{ N m}^2/\text{kg}^2.