When a firefighter at the scene of a fire is holding a heavy hose out of which water is gushing, to keep her balance, she often has to lean. Which way does she lean, forward or backward, and why?
a) Forward, to counteract the force of the water pushing her backward
b) Backward, to counteract the force of the water pushing her forward
c) Sideways, to counteract the force of the water pushing her laterally
d) Upward, to counteract the force of gravity pulling her downward
