Projectile Motion: Water Balloon Launch Project

[jrocco]

For a water balloon launch project, our students need to calculate the distance that the balloon will travel given the following information:

K- the spring constant of the launcher
the mass of the water balloon
the angle of launch
the distance that the launcher is pulled back.

Can anyone provide the sequence of equations (step by step) that leads to the students determining the distance that the balloon will travel?

I simply want them to tell me where to sit and they will launch their balloon (given the conditions above) and hopefully hit me.

Thanks

 

[berkeman]

For a water balloon launch project, our students need to calculate the distance that the balloon will travel given the following information:

K- the spring constant of the launcher
the mass of the water balloon
the angle of launch
the distance that the launcher is pulled back.

Can anyone provide the sequence of equations (step by step) that leads to the students determining the distance that the balloon will travel?

I simply want them to tell me where to sit and they will launch their balloon (given the conditions above) and hopefully hit me.

Thanks

Welcome to the PF.

I would think that you would want them to miss you, not hit you...

Are you familiar with the kinematic equations of motion for constant acceleration (the acceleration due to gravity in this case)?

http://en.wikipedia.org/wiki/Kinematics#Kinematics_of_constant_acceleration

.

 

[da_nang]

I'd first use the conservation of energy to calculate the initial velocity of the balloon once it's launched. Namely, potential energy in the spring becomes kinetic energy, if all other energy transformations are negligible. After that, do what berkeman said.

 

[jrocco]

I am slightly familiar with the kinematic equations. I do understand that in finding the initial velocity I use, v = squ 2(g)(h).

I am however looking for a simplified sequence of equations to givemy students. This is for a forensic science lesson related to ballistics.

So, if a student chooses to pull back the launcher 2 meters, launches a balloon with the mass of .234 kg at a 50 degree angle...how far will the balloon travel?

Thanks