Question

Question #46f0c

Answer 1

`4.69times10^14`MeV and `lamda=2.24times10^-34m`

Explanation:

a quick search in the internet suggests that Federer's average first serve at Wimbledon was about 115 mph in 2016 which is about 51 m/s.

The mass of a tennis ball is about 58g (0.058kg).

So the kinetic energy would be `KE=1/2mv^2=1/2*0.058*51^2=75J`

An electron volt = `1.6 times 10^-19 J` and a MeV = `1.6times 10^-13J`

So in MeV, the energy would be `75/(1.6times10^-13)=4.69times10^14MeV`

The de Boglie wavelength,`lamda` is given by `lamda=h/(mv)`
So `lamda=(6.63times 10^-34)/(0.058*51)=2.24times10^-34m`