Choose the correct term to complete each blank. It is (Harder/easier) to push an empty wheelbarrow than one filled with dirt. Because the dirt-filled wheelbarrow has more (Force/Speed/Mass) than the empty one, it requires more (Force/Inertia/Acceleration) to push at the same speed. A wheelbarrow containing grass clippings will require (More/Less/The Same) force to push at the same speed than a dirt-filled one because the grass clippings have less mass than dirt. Either wheelbarrow will require more force to push it uphill than downhill due to the effect of
(Friction/Inertia)