## Projectile Motion / Kinematics Lab (Only 2 Variables Given)

1. The problem statement, all variables and given/known data
So, our lab entails the students launching a projectile at a certain angle into a cup at a certain distance away. The launcher is 37 cm off of the ground and the cup is 7cm of the ground, so the Dy = 37-7 = 30cm. We will be given the angle in class and will be asked to position the cup at a certain distance. Lets say for example it is 35 degrees.

How could we solve for Dx with only two variables.
Any thoughts?

Thanks.

2. Relevant equations
tanθ = Vy/Vx

3. The attempt at a solution
I was thinking of using Vx = Vy/tanθ and then possibly substituting something in for Vy from another kinematic equation but that would require time and we are only given measuring tape, no timer.

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 Hint: we are only given measuring tape. Welcome to PF!
 Mentor Blog Entries: 10 Without knowing the initial speed of the projectile, this problem cannot be solved.

 Tags cup, lab, launcher, physics, projectile motion