Catch!

So this is a picture of my dog. Her name is Kiki. I was playing catch with her today in my backyard, so that is what I am going to write my physics blog about. Playing catch must of been tiring for her cause she looks wiped out in this pic. Anyway, there are many physics concepts involved in playing catch. First of all, there is the projectile motion of the ball, or actually, in this case it was a rope, but ya. You could use kinematic equations to find any variable. For example, if you know the initial velocity and the time, you can solve for the distance traveled. delta x = initial x velocity * time, so you can componentize the initial velocity to find the x component and then multiply that by the time.

The rope also has kinetic and potential energy. If the ground = zero potential energy, then after you throw the rope, kinetic energy is greatest and potential energy is least. At the peak, potential energy is greatest, so kinetic energy must be least because the law of conservation of energy says that the total mechanical energy stays the same. As the rope starts falling toward the ground, kinetic energy increases and potential energy decreases.

To relate this to what we are currently learning about: If I knew the mass of the rope and its change in velocity, then I could solve for the change in momentum because change in momentum = mass * change in velocity. Then I could find the impulse because impulse equals the change in momentum. These are just some of the physics concepts related to playing catch.

I thought it would be really cool to take a video of me playing catch with my dog, but right when I got my camera out, my dog lost interest in the game :( so typical. But here is the video anyway...you can see the projectile motion of the rope! I hope creepy people don't watch it...perhaps I will delete it after Doc reads this...