G — Science definition
The acceleration due to gravity near Earth's surface, about 9.8 m/s² directed downward, the same for every freely falling object regardless of mass.
Where it is taught
- Velocity & Acceleration — Motion & Kinematics, Physics & Environmental Science, Grade 12
In use
Average velocity captures the net result of a trip, instantaneous velocity captures a single moment, average speed tracks the total ground covered, and acceleration measures how the motion is changing — with g as the ready-made value for anything falling freely.
Velocity & Acceleration
Questions using g
Problem 1
A rock is dropped from rest and falls freely for 5.0 s. How fast is it moving at the end of that time? (g = 9.8 m/s²)
Answer and explanation
49 m/s
v = v₀ + gt = 0 + 9.8 × 5.0 = 49 m/s.
Problem 2
A ball is dropped from rest and falls freely for 2.0 s. How fast is it moving? (g = 9.8 m/s²)
Answer and explanation
19.6 m/s
v = v₀ + gt = 0 + 9.8 × 2.0 = 19.6 m/s.