### Home > CALC3RD > Chapter Ch9 > Lesson 9.1.1 > Problem9-13

9-13.

Multiple Choice: Assume that the acceleration due to gravity in the absence of friction is $a(t) = -10 \text{m/sec}^2$. If a ball is thrown straight up from a height of $5$ meters with an initial velocity of $20$ m/sec, then its height after $2$ seconds is:

1. $5$ m

1. $10$ m

1. $15$ m

1. $20$ m

1. $25$ m

$v(t)=\int{a(t)}dt=-10t+C$

$v(0)=20=-10(0)+C\text{ ; }C=20$

$h(t)=\int{v(t)}dt=-5t^2+20t+C$

$h(0)=5=-5(0)^2+20(0)+C\text{ ; }C=5$

Evaluate $h(2)$.