Question

a ball is thrown vertically upward from the top of a 100 foot tower, with an initial velocity of 20ft/sec. Its position function is s(t)=-16t^2+20t+100. What is its velocity in ft/sec when t=1 second

Answer 1

we are given

position function as

$s(t)=-16t^2+20t+100$

Since, we have to find velocity

so, we will find derivative with respect to t

$s'(t)=-16*2t+20*1+0$

$s'(t)=-32t+20$

$v(t)=-32t+20$

now, we can plug t=1

$v(1)=-32*1+20$

$v(1)=-12ft/sec$.................Answer