A tennis ball does not diffract through a narrow slit. This is common sense. Quantum and modern physics may have some odd ideas but a tennis ball still behaves like a tennis ball!
It behaves like a typical Newtonian "particle" with mass, momentum, kinetic energy and all the other things you have done in mechanics.
It cannot travel at the speed of light.
It doesn't behave like a wave. Why.
To display wave properties you need to perform an experiment that can show diffraction or interference. This is impossible for the tennis ball given its suggested "wavelength" and other characteristics. How could you do this?
Hence, the ball doesn't display wave properties.
Because the ball itself is so much bigger than its wave length it would be impossible for it to act as a wave because when any gap big enough for the ball to fit through would be of no where near the magnitude of the balls wave length.
(Original post by farhanyen)
I do not understand the solutions to question 2 and 5 of the same paper here.
For question 2, I thought the solution should be D but it is C. For question 5 the solution is D, I've no idea why.
For 2 I think it's because the shape suggests 0 momentum overall? I'm not sure about 5 either.