A ball is thrown vertically upward from the top of a 100-foot tower, with an initial velocity of 20 ft/sec. Its position function is s(t) = –16t2 + 20t + 100. What is its velocity in ft/sec when t = 1 second?

–12
–44
100
–32

Question

A ball is thrown vertically upward from the top of a 100-foot tower, with an initial velocity of 20 ft/sec. Its position function is s(t) = –16t2 + 20t + 100. What is its velocity in ft/sec when t = 1 second?

 –12
 –44
 100
 –32

cwrw238 · Answer

first find the derivative ds/dt which gives the the formula for the velocity
then plug in t = 1

cwrw238 · Answer

can you find the derivative/

cwrw238 · Answer

have you learnt some calculus ?  differentiation?

anonymous · Answer

it is NOT   B -32

anonymous · Answer

the correct answer is A) -12

using ( f(a+h)-f(a) ) / h, plug in a = 1 and solve
>>
>>
( h(-32 - 16h +20) ) / h
cancel and plug in h = 0
-12