Question

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 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 a red car mass of 500 kg moving at 3 m/s a green car with a mass of 500kg moving at 21 m/s

Answer 1

The kinetic energy (KE) of an object can be calculated using the formula:

\[
KE = \frac{1}{2} m v^2
\]

where \( m \) is the mass of the object and \( v \) is its velocity. Since all the cars have the same mass of 500 kg, we only need to compare their velocities to determine which has the greatest kinetic energy.

Let's calculate the kinetic energy for each car:

1. **Blue car**:
\[
KE = \frac{1}{2} \times 500 \, \text{kg} \times (30 \, \text{m/s})^2 = 0.5 \times 500 \times 900 = 225000 \, \text{J}
\]

2. **Yellow car**:
\[
KE = \frac{1}{2} \times 500 \, \text{kg} \times (12 \, \text{m/s})^2 = 0.5 \times 500 \times 144 = 36000 \, \text{J}
\]

3. **Red car**:
\[
KE = \frac{1}{2} \times 500 \, \text{kg} \times (3 \, \text{m/s})^2 = 0.5 \times 500 \times 9 = 2250 \, \text{J}
\]

4. **Green car**:
\[
KE = \frac{1}{2} \times 500 \, \text{kg} \times (21 \, \text{m/s})^2 = 0.5 \times 500 \times 441 = 110250 \, \text{J}
\]

Now we compare the kinetic energies:

- Blue car: 225,000 J
- Yellow car: 36,000 J
- Red car: 2,250 J
- Green car: 110,250 J

The blue car has the greatest kinetic energy of **225,000 J**.