Question

Please help.

Which has the greatest net force?
A 30-kg box falling from a window, with air resistance
A 2,000-kg car with a constant velocity of 35 m/s
A 30-kg box falling on the Moon
A 2-kg soccer ball accelerating at 22 m/s2

Answer 1

The answer would be the box with air resistance.

Since the car has a constant velocity, there is no acceleration and the force is 0.

For the box on the moon, the acceleration is significantly less than on earth, even with air resistance.

For the soccer ball, the net force is F=ma=(2)(22) = 44N, which is not a lot considering even the ball on the moon would have more force than that.

Then that leaves us with the ball with air resistance.