With what velocity will an object strike the ground when dropped from a height of 100 m?

Correct answer: a 44.27 ms⁻¹

v² = 2gh = 2 × 9.8 × 100 = 1960, so v = √1960 = 44.27 ms⁻¹.

Why the other options are wrong

• b 43.27 ms⁻¹: 43.27 ms⁻¹ is close, but √1960 = 44.27. The square root has to be worked out properly.
• c 42.27 ms⁻¹: 42.27 ms⁻¹ does not fit: 42.27² is about 1787, while 2gh = 1960.
• d 41.27 ms⁻¹: 41.27 ms⁻¹ does not fit: 41.27² is about 1703, while 2gh = 1960.