clipperdude21

1. A ball is launched with a velocity of 1000m/s at some angle theta. The ball must travel 2000m in the x dir and land 800m in the y dir on a plateau. What theta should the ball be shot at to make this happen.

2. y=y0 +v0t -.5gt^2

3. I solved for t using x=v0cos(theta)t and plugged that into the y equation and got one solution. The answer key says there's two solutions. One at 20 something, which is the one i got and also one at 89.4 degrees. Can someone show me how to get the other/both solutions

THANKS! I appreciate it

sunumen
You should use the formula
y=x tan theta - $$\stackrel{gx^2}{2u^2cos^2 theta}$$

THis formula is combined by
verticial component using s=ut+1/2 at^2
horizontal component v=s/t

clipperdude21
i used that equation and still only got 22.4 degrees at the sole solution... 89.4 doesn't seem to fit. Is there an error in the answer key?

sunumen
i also get the 22.4 degree
but it is acceptable that there is another angle is the answer...
however I forget how to solve it ~sorry

clipperdude21
ok thanks anyway!