Net Force Determines Motion

Steps:

• Resolve forces into components: horizontal (20 N left, 20 N right) and vertical (12 N up, 12 N down).
• Calculate net horizontal force: 20 N right - 20 N left = 0 N.
• Calculate net vertical force: 12 N up - 12 N down = 0 N.
• Total net force is zero, so by Newton's first law, the object moves with constant velocity in a straight line.

Why B is correct:

• Zero net force means constant velocity (Newton's first law), which is straight-line motion at constant speed.

Why the others are wrong:

• A: No acceleration occurs with zero net force.
• C: Speed remains constant, not decreasing.
• D: Momentum stays constant, not increasing.

Final answer: B