Puppy rides a skateboard for the first time
My Puppy wants to ride a skateboard and be the most popular dog in the neighborhood so she does.
I place my skateboard on a 15 degree tilted hill. Next, I take my dog and place her on top of my skateboard. Then, I give the skateboard a push and she starts rolling down the hill. Suddenly, we see a frisbee in the middle of the passageway and next thing you know..... BOOM! My dog goes flying in the air and lands on the grass. As you can see, she was in motion at a constant velocity and then she was knocked down by an external force (the frisbee). The frisbee was an inertia because it was not moving at all.