Answer:
Explanation:
Given
average speed of Phelps [tex]v_{avg}=2\ m/s[/tex]
total distance [tex]d=200\ m[/tex]
he swims first 100 m at an average speed if [tex]1.8 m/s[/tex]
so time taken is [tex]t_1=\frac{100}{1.8}=55.55\ s[/tex]
suppose [tex]t_2[/tex] is the time taken to swim remaining half
average velocity is [tex]v_{avg}=\frac{displacement}{total\ time}[/tex]
[tex]v_{avg}=\frac{100+100}{55.55+t_2}[/tex]
[tex]t_2+55.55=\frac{200}{2}=100[/tex]
[tex]t_2=44.45\ s[/tex]
so velocity in the second half is
[tex]v_2=\frac{100}{45.45}[/tex]
[tex]v_2=2.19\approx 2.2\ m/s[/tex]
