Play Fetch? Can you?
You are an alien living in a far off planet, your dog can run at a maximum speed of 40kmph and has a uniform acceleration of 1mps^2. You want to play fetch with him, but the problem is that you are travelling in a train and the opposite wall is just 5 metres away. You can throw the ball at a uniform velocity of 2 ms^-1 at any angle you desire. So what should be the angle with the horizontal you should throw the ball so that your dog is able to catch the ball in the air, just before the opposite wall? Answer is in degrees. Gravity is approx. 1/26 of that of Earth.