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?

Answer 1

-12
–44
100
–32

Answer 2

-16t^2

Answer 3

@Compassionate @Aamirgsen @cwrw238 @iambatman @Callisto @uri @eliassaab @hba @PRAETORIAN.10

Answer 4

do you know how to find the formula for the velocity ?
Can you find ds/dt?

Answer 5

this is calculus.

Answer 6

to find velocity we do just find the derivative

Answer 7

right

Answer 8

@cwrw238

Answer 9

i get -32t + 20 i just dont know wht do do afterwards

Answer 10

yes the derivative is correct.
then set t=1

Answer 11

because you need the velocity at 1 second (at t=1)

Answer 12

so -32(1)+12=-12 is tht right then wht else do i do

Answer 13

nothing you are done.

Answer 14

you found the velocity when t=1

Answer 15

how r u sure

Answer 16

fakee is correct -12

Answer 17

okay...cool can you guys help me with another problem?

Answer 18

you have a position function, they ask you to find the velocity at t=1.
so you find the veloicty function, (which is s'(t), the derivative)
and plug in t=1.

basically, you were asked s'(1).

Answer 19

What is the instantaneous slope of y=8/x at x=-3

Answer 20

f(x)=8/x
instantaneous rate at x=a, is f'(a)

Answer 21

so 8

Answer 22

f '(a), I said:)

Answer 23

i meant -3

Answer 24

find the derivative fisrt

Answer 25

first*

Answer 26

which is 1/x

Answer 27

no

Answer 28

no - do you know what the derivative of 1/x is?

Answer 29

1/x is same as x^-1.

Answer 30

use the power rule.

Answer 31

its 1

Answer 32

\[\frac{d}{dx} x^n= nx^{x-1}\]

Answer 33

8 is a k so 0???

Answer 34

\[\frac{d}{dx} x^{-1}= ?\]

Answer 35

8

Answer 36

i dont know how to do thios

Answer 37

this

Answer 38

the power rule:\[\frac{d}{dx} x^n= nx^{x-1}\]your question:\[\frac{d}{dx} x^{\color{red}{-1}}= ({\color{red}{-1}})x^{{\color{red}{-1}~-1}}\]

Answer 39

what do you get for the derivative?
(I am using d/dx notation for the derivative)

Answer 40

solving

Answer 41

and you get?
or still lost?

Answer 42

ya

Answer 43

when you did