Question

Im having trouble with a hw problem. So a kid kicks a ball horizontally at 15m/s down a hill that is 45 degrees. I need to find the time the ball hits the ground. Any help setting this up would be appreciated!

Answer 1

you need to tell us how tall this hill is...

Answer 2

3.03 seconds assuming the hill is 45 meters tall.

-45=.5(-9.8)t^2

solve for t.

Answer 3

That is all the information given, the exact problem says "A rock is kicked horizontally at 15 { m/s} from a hill with a 45 degree slope ."

Answer 4

but without the height of the hill, we don't know how far the ball has to travel to hit the ground.

Answer 5

I know I have to use Vx=Vcos(theta) and Vy=Vsin(theta), and knowing gravity is -9.8m/s2 I need to solve for t with the kinematic equations, im just not sure which one

Answer 6

based on the information you've given, you don't have enough information to solve for T. Are you sure no distance was given?

Answer 7

Also, if the ball is just kicked horizontally, I don't see how theta plays a role since theta would equal 0.

Answer 8

well the fact that the problem tells you the slope of the hill I figured you need that value in order to solve the problem?

Answer 9

That depends on what you need to solve. If you're just trying to solve how long it takes for the ball to hit the ground, it's much more useful to know how high up you start first. The angle could come into play if the ball lands on the hill rather than at the bottom of the hill, but you still need to know where you're starting from.