Answer:
8.19 kg m/s
Explanation:
The change in momentum is equal to the impulse. This impulse is also calculated as the force times time, so
[tex]\Delta p=F\cdot t[/tex]Then, replacing F = 39 N and t = 0.21 s, we get:
[tex]\Delta p=(39N)(0.21s)=8.19\text{ kg m/s}[/tex]So, the change in momentum of the tennis ball is 8.19 kg m/s