Animation Black Screen


I am trying to do a simple pendulum animation for school, and once I finished I saved it as an .mov but when I look at it in the movie player, the screen is black and my animation doesn’t show. Does anyone here know how to fix this so it has a white background so others can see the animation?? I attached the file to show you what it looks like. Thanks!

You need to add a colour card to get rid of the black background. Or you could just create a layer and put a coloured square on it as a background and extend the exposure the length of the scene.