A freely falling object covers 25 m in 5 s. How much more distance will it cover in the 6th second?

Think it through first, then pick an option.

Answer and explanation

Correct answer: c 11 m

From h ∝ t², in 6 s h = 25 × (6/5)² = 36 m. In the 6th second it is 36 − 25 = 11 m.

Why the other options are wrong

a 36 m: 36 m is the total distance in the first 6 s (25 × 36/25). The question asks only for the 6th second.
b 30 m: 30 m comes from no correct step. Take h ∝ t², find the total for 6 s and subtract the 5 s total.
d 5 m: 5 m is 25 ÷ 5, the average per second. As the velocity keeps rising the 6th second covers more than that.