Question

The mass of a golf ball is 45.9

Answer 1

The equation for the de Broglie wavelength is: 
λ = (h/mv) √[1-(v²/c²)], 
where h is Plank's Constant, m is the rest mass, v is velocity, and c is the velocity of light in vacuum. However, if c>>v (and it is, in this case) then the expression under the radical sign approaches 1, and the equation simplifies to: 
λ = h/mv. 
Substituting, (remember to convert the mass to kg, since 1 J = 1 kg·m²/s²): 
λ = (6.63x10^-34 J·s) / (0.0459 kg) (72.0 m/s) = 2.00x10^-34 m.