Question

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

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

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

Oa 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

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 the velocity.

For each car, since they all have the same mass (500 kg), we can compare their kinetic energies based on their velocities:

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

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

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

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

Now let's summarize the kinetic energies:

- Red car: 2250 J
- Blue car: 225000 J
- Green car: 110250 J
- Yellow car: 36000 J

The object with the greatest kinetic energy is the **blue car**, with 225000 J.