Question

Got a Calculus Question:
You shoot a rifle at an angle of 26 degrees. The bullet leaves your rifle at a height of 6 feet and a speed of 863 feet per second. It hits the ground after seconds at a distance of feet.

Answer 1

this assumes you know the parametric formulas to apply

Answer 2

aaand that I do not know.

Answer 3

x(t) = vo cos(a) t

y(t) = -16t^2 + vo sin(a) t + ho

Answer 4

so the 6 feet I will use in the y(t) equation, right?

Answer 5

yep, also the initial velocity and the angle

Answer 6

so x(t)=863(cos(26))

Answer 7

the equation for y is therefore a quadratic in t, solve for t that zeros it out

when we know when height = 0 we know the time it takes to use in the x equation

Answer 8

y(t)=-16t^2+863(sin(26)(t))+6

Answer 9

so set that equation equal to zero and solve for t?

Answer 10

yep y = 0, solve for t

Answer 11

would that just be the quadratic formula, or is it different because there is a sin in there?

Answer 12

863 sin(26) is just some number, the quad formula is fine

Answer 13

I plugged that in and got 41.139611725, but I got that it was wrong(this is for y).

Answer 14

0 = 16t^2+863t sin(26)+6

this works out to be about 23.66

Answer 15

therefore the distance traveled along the x axis is about 863(23.66) cos(26)

Answer 16

I did 23.66 and that didn't get the answer either.

Answer 17

41 is what wee get when we use 26 radians

Answer 18

can you take a screen shot of the problem?

Answer 19

ok so I got 23.660492935, and it isn't taking that either.

Answer 20

Correction, that was the answer for the x(seconds after hitting the ground)

Answer 21

it may be asking for so many decimals, or a round or something

Answer 22

yes, time it takes to hit the ground, 23.66

Answer 23

I got 775.659261956 for the distance, not taking that.

Answer 24

how far it went, assuming a horizontal distance is being asked for ...

x(t) = vo t cos(a)

Answer 25

make sure your calculator is reading degrees, and not radians

Answer 26

ya, I did cos26 degrees times 863.

Answer 27

http://www.wolframalpha.com/input/?i=863%2823.66%29cos%2826%29

Answer 28

you didnt multiply it by the time we found did you

Answer 29

No I didn't, haha, just realized that.

Answer 30

That did it, thank you so much!

Answer 31

youre welcome