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Which object has the greatest kinetic energy?(1 point)

Responses

a blue car with a mass of 500 kg moving at 30 m/s
a blue car with a mass of 500 kg moving at 30 m/s

a green car with a mass of 500kg moving at 21 m/s
a green car with a mass of 500kg moving at 21 m/s

a yellow car with a mass of 500 kg moving at 12 m/s
a yellow car with a mass of 500 kg moving at 12 m/s

a red car mass of 500 kg moving at 3 m/s

1 answer

To determine which object has the greatest kinetic energy, we can use the formula for kinetic energy (KE):

\[ KE = \frac{1}{2}mv^2 \]

where \( m \) is the mass of the object and \( v \) is its velocity.

We can calculate the kinetic energy for each car:

  1. Blue car:

    • Mass \( m = 500 \) kg
    • Velocity \( v = 30 \) m/s
    • \( KE = \frac{1}{2} \times 500 \times (30)^2 = \frac{1}{2} \times 500 \times 900 = 225000 \) J

  2. Green car:

    • Mass \( m = 500 \) kg
    • Velocity \( v = 21 \) m/s
    • \( KE = \frac{1}{2} \times 500 \times (21)^2 = \frac{1}{2} \times 500 \times 441 = 110250 \) J

  3. Yellow car:

    • Mass \( m = 500 \) kg
    • Velocity \( v = 12 \) m/s
    • \( KE = \frac{1}{2} \times 500 \times (12)^2 = \frac{1}{2} \times 500 \times 144 = 36000 \) J

  4. Red car:

    • Mass \( m = 500 \) kg
    • Velocity \( v = 3 \) m/s
    • \( KE = \frac{1}{2} \times 500 \times (3)^2 = \frac{1}{2} \times 500 \times 9 = 1125 \) J

Now, comparing the kinetic energies:

  • Blue car: 225000 J
  • Green car: 110250 J
  • Yellow car: 36000 J
  • Red car: 1125 J

The blue car has the greatest kinetic energy of 225000 J.