How fast must a 54g tennis ball travel in order to have a de Broglie wavelength that is qual to that of a photon of green light 54000Å ?

Explanation

Given : de Broglie wavelength of the tennis ball equal to 5400 Å.
`m = 54 g`
`v = ?`
`lambda = h/(m V)`
`V = h/(m lambda)`
`V = (6.626 xx 10^(-34)JS)/(54 xx 10^(-3) Kg xx 5400 xx 10^(-10)m)`
`V = 2.27 xx 10^(-26) ms^(-1)`.