Answer:
Kinetic frictional force will be equal to 56.84 N
Explanation:
We have given mass of the skier m = 58 kg
Acceleration due to gravity 
Coefficient of kinetic friction 
We have to find the kinetic frictional force
Kinetic frictional force is given by

So kinetic frictional force will be equal to 56.84 N
Answer:
t = 180 / 1.4 = 129 sec (time to swim horizontally across river)
S = 129 sec * V where V is speed of current and S is the distance he will be carried downstream
The problem does not specify V the speed of the river
The energy the electron gives up passing between the electrodes is equal to the product between its charge and the potential difference between the electrodes:

where
e is the electron charge

is the potential difference
Plugging numbers into the equation, we find that the electron gives up is