Question

If a stone is tossed from the top of a 310 meter building, the height of the stone as a function of time is given by h(t) = -9.8t^2 – 10t + 310, where t is in seconds, and height is in meters. After how many seconds will the stone hit the ground? Round to the nearest hundredth’s place; include units in your answer.

Answer 1

are you sure that is the function to be used?

Answer 2

- 10 would indicate being tossed up first

Answer 3

yes

Answer 4

or thrwon down?

Answer 5

310=-9.8t^2-10t+310
=>-9.8t^2-10t=0
=>t=0 or t=-10/9.8 .......

Answer 6

then this is not happening on earth :)

Answer 7

-4.9 ....

Answer 8

correct

Answer 9

why ans is negative?

Answer 10

solve h(t)=0 for t

Answer 11

i think -(time) means before 4.9 sec when ball is thrown...ball is assumed to be on the ground

Answer 12

the equation used for any problem dealing with gravity (on earth) comes from the fact that acceleration due to gravity is a constant. -9.8 meters per second per second.

a(t) = -9.8
v(t) = -9.8 t + C, where at time 0, we have an initial
velocity of -10; t=0, then C = -10

v(t) = -9.8 t -10

h(t) = -4.9 t^2 -10t + C; where at t=0, the initial height is
off a building that is 310 meters
tall: C = 310

h(t) = -4.9 t^2 -10t + 310

Answer 13

the equation as presented in the posting, has gravity having way to large of an effect

Answer 14

thanks amistre

Answer 15

yep ;)

at any rate, the equation should be solved for h(t) = 0 so you know at what time it takes for it to hit the ground