Conservation of Mechanical Energy

Steps:

• The ball starts with gravitational potential energy at point 1 (top height) and zero kinetic energy.
• As it falls, potential energy converts to kinetic energy due to gravity.
• Ignoring air resistance, no energy is lost to friction or other non-conservative forces.
• Total mechanical energy (potential + kinetic) remains constant throughout the motion.

Why A is correct:

• The law of conservation of energy states that in a closed system without dissipative forces, total mechanical energy is constant, so it is the same at all points.

Why the others are wrong:

• B: Total energy is not greatest at point 1; potential energy is maximum there, but kinetic is zero, equaling the total at other points.
• C: Total energy is not greatest at point 2; it is midway in conversion, but overall total remains unchanged.
• D: Total energy is not greatest at point 3; kinetic energy is maximum there, but potential is zero, matching the total elsewhere.

Final answer: A