A bullet is shot upwards and its trajectory can be modeled by the function h(t) = -t4 + 15t3 - 150t2 + 1600t + 3000, where h(t) is measured in meters and t is the number of seconds since the bullet is shot. At what second did the bullet hit the ground?

Select one:
a. 13.73 seconds
b. 15.32 seconds
c. 9.79 seconds
d. 8.09 seconds

Question

A bullet is shot upwards and its trajectory can be modeled by the function h(t) = -t4 + 15t3 - 150t2 + 1600t + 3000, where h(t) is measured in meters and t is the number of seconds since the bullet is shot.  At what second did the bullet hit the ground?

Select one:
a. 13.73 seconds
b. 15.32 seconds
c. 9.79 seconds
d. 8.09 seconds

1645323 · Answer

@DDCamp

cwrw238 · Answer

hint: at ground level h(t) = 0

1645323 · Answer

so the answer is the x coordinate on the right side?

1645323 · Answer

i got 9.477

cwrw238 · Answer

if you are talking aBOUT THE GRAPH OF THE FORMULA ITS THE VALUE OF X WHERE the graph cuts the x axis  on right hand side  yes

mathmale · Answer

@1645323 :   There are two very different situations here.  One is to set the given equation = to 0 and then to solve for t; the results would include a t value greater than zero.

The other is to let t = 0.  Then h(0)=3000, but that is NOT what we're looking for.  that would be the "vertical intercept" and would represent the starting height of the bullet.

mathmale · Answer

@1645323 :    Rather than say, "i got 9.477," please say:  "my calculations show that the bullet hits the ground 9.477 seconds after it was fired from the gun."  Need to identify the variable involved; that variable is time, t.  Good luck.

cwrw238 · Answer

|dw:1396540951534:dw|