Let h(t) represent the height of the projectile after t seconds. If the projectile is being launched from the ground, then h(0)=0, and h(t)=-4.9t²+98t. When the equation is in this form, the maximum height is determined by -98/2(-4.9), or after 10 seconds. Thus -4.9(100)+98(10)=490 m as the highest point of the projectile Then, when it hits the ground, h(t)=0, so 0=-4.9t²+98t 98t=4.9t² 4.9t=98 t=20 ☺☺☺☺
