Question

lana pushes a heavy box, but it does not move. she asks sam to push it too, and when they both push, the box slides across the floor. which term best describes the forces acting on the box that cause it to move?
unbalanced
balanced
normal
gravitational

Explanation:

1. Recall the definitions of each force - related term:

• Unbalanced forces: When the net force on an object is not zero, and this causes a change in the object's motion (like starting to move, speeding up, slowing down, or changing direction).
• Balanced forces: When the net force on an object is zero, so the object remains at rest or moves at a constant velocity (no change in motion).
• Normal force: The force exerted by a surface to support the weight of an object resting on it, acting perpendicular to the surface. It doesn't cause horizontal motion in this context.
• Gravitational force: The force of attraction between two objects due to their masses, acting vertically (downward on the box due to Earth's gravity) and not causing horizontal motion here.

1. Analyze the scenario:

• Initially, when Lana pushes the box and it doesn't move, the forces (her push, friction, normal force, gravity) are balanced (net force = 0).
• When Sam joins and they both push, the box moves. This means the combined push force is greater than the opposing forces (like friction), so the net force is not zero. Thus, unbalanced forces are acting on the box to cause the motion.

Answer:

A. unbalanced