h = height from which the pole vaulter falls = 7 m
v₀ = initial velocity of pole vaulter at height "h" = 0 m/s
v = final velocity of pole vaulter as he hits the ground = ?
g = acceleration due to gravity = 9.8 m/s²
m = mass of pole vaulter
using conservation of energy
kinetic energy just before he hits the ground = potential energy at the top + kinetic energy at the top
(0.5) m v² = (0.5) m v₀² + mgh
(0.5) v² = (0.5) v₀² + gh
v² = v₀² + 2gh
inserting the values
v² = (0)² + 2(9.8 x 7)
v = 11.7 m/s
