1. ## Word Problem

A projectile is shot upwards with an initial velocity of 30m/s. Its height at time t is given by h=30t-4.9t^2. During what period of time is the projectile more than 40m above the ground? Express your answer rounded to the nearest hundredths.

2. $40=30t-4.9t^2$
$t=\frac{-30+\sqrt{900-784}}{2(-4.9}$
$
$t=\frac{150\pm10\sqrt{29}}{49}$
$t_1=4.16$
$t_2=1.96$