Science Buddies: "Ask an Expert"

I am have a hard time understanding what I need to do. In the project it gives equations and one of them is finding the initial velocity so I can predicts the points on the table. I have a lot of the other variables but am having a hard time finding understanding how to do this. I have m=2.7g, r=22.1 cm, L=24.3cm, l=1.1*10^-3 kg*m^2, x subscript 0= 8.382cm, and k=33.44 N/m^1/2. If someone could help just clarify how to to find the initial velocity that would be awesome. This is a little urgent and help as soon as possible would be very nice. Thank you!

Hi - the equation you're looking for is Equation 16 in the introduction of the project, but note the text just below the equation - "You will have to do some algebra to rearrange Equation 16 to solve for our unknown variable — the launch velocity of the ball, v2."

You need to do the algebra to rearrange Equation 16 to solve for v2 before you can then use equations 8 and 10 to calculate the trajectory of the ball.

Hope that helps,

Ben