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Use the table of information to answer the question.

Fruit

Mass (kg)

4

4

Speed (m/s)

2

4

Watermelon A

Watermelon B

Two watermelons fall off a kitchen counter. The masses and speeds of the fruits are in the table. How do the kinetic and/or the potential energies of the fruits compare? (1 point)

The watermelon A has more kinetic energy.

Both fruits have the same kinetic and potential energy.

Both fruits have only potential energy and no kinetic energy.

The watermelon B has more kinetic energy.

1 answer

To compare the kinetic and potential energies of the two watermelons, we can use the formulas for kinetic energy (KE) and potential energy (PE).

  1. Kinetic Energy (KE) is calculated using the formula: \[ KE = \frac{1}{2} mv^2 \] where \( m \) is the mass and \( v \) is the speed.

  2. Potential Energy (PE) at a certain height is given by: \[ PE = mgh \] where \( g \) is the acceleration due to gravity and \( h \) is the height. Since both watermelons fall from the same height, they will have the same potential energy just before they fall.

Given Information:

  • Watermelon A:

    • Mass = 4 kg
    • Speed = 2 m/s

  • Watermelon B:

    • Mass = 4 kg
    • Speed = 4 m/s

Calculate Kinetic Energy:

  • For Watermelon A: \[ KE_A = \frac{1}{2} \times 4 , \text{kg} \times (2 , \text{m/s})^2 = \frac{1}{2} \times 4 \times 4 = 8 , \text{J} \]

  • For Watermelon B: \[ KE_B = \frac{1}{2} \times 4 , \text{kg} \times (4 , \text{m/s})^2 = \frac{1}{2} \times 4 \times 16 = 32 , \text{J} \]

Conclusion:

  • Kinetic Energy: Watermelon B has more kinetic energy (32 J) compared to Watermelon A (8 J).
  • Potential Energy: Since both watermelons start from the same height and have the same mass, they will have the same potential energy just before they fall.

Based on this analysis, the correct answer is: The watermelon B has more kinetic energy.