Answer
Each player must pull with a force of 508 N
Work Step by Step
Since the sled moves at a steady speed, the acceleration is zero, so the net force on the sled is also zero. The sum of the forward-pointing component $F_x$ of each player's force $F$ must be equal in magnitude to the friction force. Therefore;
$2~F_x = F_f$
$2~F~cos(10^{\circ}) = F_f$
$F = \frac{1000~N}{2~cos(10^{\circ})}$
$F = 508~N$
Each player must pull with a force of 508 N.
