The net torque acting on an object is zero. What can you say about the angular momentum (about the same axis) of the object?

The angular momentum (about the same axis) of the object is constant

Explanation:

Torque is the time time derivative of angular momentum.

τ = dL / dt

where;

dL  is the change in  angular momentum

τ is torque acting on the object

dt is change in time

when net torque acting on an object is zero, then

dL / dt = 0

Change in angular momentum (ΔL) is zero, therefore we can say that the angular momentum (L) is constant.

Thus, the angular momentum (about the same axis) of the object is constant.

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min