Hard
An object is dropped from a height of 20 m. Find the time it takes to reach the ground. (Take g = 10 m/s², ignore air resistance)
Explanation
Explanation
Using h = ½gt²: 20 = ½(10)t², so t² = 40/10 = 4.0, giving t = 2 s.
PRO TIP
Re-check your working by substituting the answer back into the original question.