Question

A golf ball of mass 0.05 kg struck by a golf club of mass 𝑚 kg with speed 50 𝑚/𝑠 will have
an initial speed of 𝑢(𝑚) =
83𝑚
𝑚+0.05
m/s. Verify that 𝑢
′
(𝑚) > 0. Compare 𝑢′(0.15) and
𝑢′(0.20) in terms of the speed and mass of the ball.

Answer 1

that copy/paste isn't working out so well, is it?
if u(m) = 83m+0.5
then u'(m) = 83

I suspect a typo, since you said it had an initial speed of 50 m/s
Maybe you can clear things up a bit ...