Free fall: distance fallen
An object is dropped from rest. Ignoring air resistance and using g = 10 m/s², how far does it fall in 3 s?
Answer C: explanation for every choice
A
This uses d = gt/2, which has the wrong units.
B
30 m/s is the object's speed after 3 s, not the distance.
C
Correct. d = ½gt² = ½(10)(3²) = 45 m.
D
This leaves out the ½ in d = ½gt².
TakeawayFrom rest: d = ½gt² and v = gt.
Equation usedDisplacement with constant acceleration
Next question →Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID cp55.