Ahockey puck is set in motion across a frozen pond. if ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is a) zero. b) equal to its weight divided by its mass. c) equal to the product of its mass times its weight.

Zero

Explanation:

According to Newton's second law, the net force acting on an object is equal to the product between the object's mass and its acceleration:

F = ma

For the hockey puck, there are no forces acting on it during its motion, since ice friction and air resistance are negligible. This means that the net force is zero:

F = 0

But this means that the acceleration is also zero:

a = 0

So the hockey puck is moving already at constant velocity. Therefore, there is no need for additional forces.

the answer would be a

d. air pressure decreases as altitude increases.