A ball is released from rest and falls freely for 5 s. Taking $g = 10$ m/s$^2$, its velocity on reaching the ground is:

1. Use $v = u + at$ with $u = 0$ and $a = g = 10$ m/s$^2$. 2. Substitute the time $t = 5$ s. 3. $v = 0 + 10 \times 5 = 50$ m/s. 4. 10 m/s is just the value of $g$, not the final velocity, so it is the trap. _Source: Balbharati (Maharashtra Board) Class 10 Science & Technology, Ch 1 "Gravitation", p.21_