The height h (in metres) of a ball thrown vertically upward from the top of a cliff…

MATHEMATICS · Subjective · GCSE · Mathematics · Algebra · Algebra

Problem

The height h (in metres) of a ball thrown vertically upward from the top of a cliff is given by

h = -5t^{2} + 45t + 100,

where t is the time in seconds after it is thrown. After how many seconds will the ball reach the ground at the foot of the cliff?