1. a ball's position, in meters, as it travels every second is represented by the position function s(t) = 4.9t2+ 450.

what is the velocity of the ball after 5 seconds? with units

2.the cost in dollars of producing x units of a particular camera is c(x) = x2 – 1.

find the average rate of change of c with respect to x when the production level is changed from x = 100 to x = 101. include units in your answer.
find the instantaneous rate of change of c with respect to x when x = 100. include units in your answer.

1) The ball's position is described by:
s(t) = 4.9t² + 450
We want to find the velocity, which is the 1st-order derivative of the displacement function (I assume this is an introductory calculus class)
s'(t) = v(t) = 9.8t           
We get this by multiplying 4.9 x 2 and reducing the exponent by 1. Now we simply plug 5 in for t.
v(5) = 9.8* 5
v(5) = 49m/s

2) Our cost function is C(x) = x² - 10,000
To find the average rate of change between these units, we use this formula:
( C(101) - C(100) ) ÷1 .
We find the change in C, and divide by the change in x, which is just one. 
C(101) = 101² - 10,000
C(101) = 201

C(100) = 100² - 10,000
C(100= 0

C(101) - C(100) = 201 
Average rate of change in cost is 201 dollars/ unit between the two points.