math 151 question

Question

The table below shows the height, , in meters, of an object that is thrown off the top of a building as a function of , the time in seconds after it is thrown.

t 0.5	1	1.5	2	2.5	3
h(t) 74.275	83.1	89.475	93.4	84.875	93.9

Using your calculator to do a quadratic regression, the height of the object as a function of the number of seconds that have passed since the object was thrown can be expressed by: .

Using your quadratic regression from above, how high will the object be 2.6 seconds after it is thrown? Round to 3 decimal places.

Using your quadratic regression, how long will it take the object to reach 11 meters? 

Answer 1

h= -4.9(2.6)^2+25(2.6)+63

= -33.124+65+63

=31.876+63

= 94.876 meters high in 2.6 seconds

11= -4.9t^2+25t+63

4.9t^2-25t -52=0

use quadratic formula

t= 25/9.8 +(1/9.8)sqr(625+4(4.9)(52))

t=about 7 seconds to reach 11 meters