Time equals energy divided by power

Steps:

• Battery supplies 3000 J of energy to the motor.
• Motor power is 2.0 W, or 2 J/s.
• Calculate time in seconds: t = energy / power = 3000 J / 2 J/s = 1500 s.
• Convert to minutes: 1500 s ÷ 60 s/min = 25 min.

Why D is correct:

• The formula t = E / P directly gives 25 minutes when E = 3000 J and P = 2 W, as power defines energy use rate.

Why the others are wrong:

• A requires 2 W × 150 min × 60 s/min = 18,000 J, exceeding supplied energy.
• B requires 2 W × 100 min × 60 s/min = 12,000 J, exceeding supplied energy.
• C requires 2 W × 50 min × 60 s/min = 6,000 J, exceeding supplied energy.

Final answer: D