Question

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

a truck with a mass of 3,500 kg moving at 30 m/s

a person with a mass of 73 kg running 6 m/s

a locomotive engine with a mass of 205,000 kg moving 5 m/s

a fast pitched baseball with a mass of .5 kg moving at 46.9 m/s

Answer 1

To determine which object has the greatest kinetic energy, we can use the kinetic energy formula:

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

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

Let's calculate the kinetic energy for each object:

1. **Truck**:
- Mass (\( m \)) = 3500 kg
- Velocity (\( v \)) = 30 m/s
\[ KE = \frac{1}{2} \times 3500 \times (30)^2 = \frac{1}{2} \times 3500 \times 900 = 1575000 \, \text{J} \]

2. **Person**:
- Mass (\( m \)) = 73 kg
- Velocity (\( v \)) = 6 m/s
\[ KE = \frac{1}{2} \times 73 \times (6)^2 = \frac{1}{2} \times 73 \times 36 = 1314 \, \text{J} \]

3. **Locomotive**:
- Mass (\( m \)) = 205,000 kg
- Velocity (\( v \)) = 5 m/s
\[ KE = \frac{1}{2} \times 205000 \times (5)^2 = \frac{1}{2} \times 205000 \times 25 = 2562500 \, \text{J} \]

4. **Baseball**:
- Mass (\( m \)) = 0.5 kg
- Velocity (\( v \)) = 46.9 m/s
\[ KE = \frac{1}{2} \times 0.5 \times (46.9)^2 = \frac{1}{2} \times 0.5 \times 2198.41 \approx 549.10 \, \text{J} \]

Now, let's summarize the kinetic energies calculated:

- Truck: 1,575,000 J
- Person: 1,314 J
- Locomotive: 2,562,500 J
- Baseball: 549.10 J

**The object with the greatest kinetic energy is the locomotive engine with 2,562,500 J.**