Total mechanical energy of the cannon ball

Steps:

• Identify components: total energy E = kinetic energy (KE) + gravitational potential energy (PE).
• Calculate KE = (1/2) × mass × velocity² = (1/2) × 3.0 × (22.0)² = 726 J.
• Calculate PE = mass × g × height, where g is acceleration due to gravity = 3.0 × g × 6.0 = 18g J.
• Add them: E = 726 + 18g J; g not specified (typically 9.8 or 10 m/s²).

Why D is correct:

• Not enough information to compute numerical value without specified g.

Why the others are wrong:

• A: Too low; ignores most KE.
• B: Underestimates total; possible if only KE approximated low.
• C: Underestimates total; possible if PE miscalculated with low g or h.

Final answer: Not enough information.