Question

Which object has the greatest kinetic energy?(3 points)
Responses

a truck with a mass of 3,500 kg moving at 30 m/s
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 person with a mass of 73 kg running 6 m/s

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

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

Answer 1

Compute KE = 1/2 m v^2 for each:

- Truck: 0.5(3500)(30^2) = 0.5(3500)(900) = 1,575,000 J
- Person: 0.5(73)(6^2) = 0.5(73)(36) = 1,314 J
- Baseball: 0.5(0.5)(46.9^2) = 0.25(2199.61) ≈ 550 J
- Locomotive: 0.5(205,000)(5^2) = 0.5(205,000)(25) = 2,562,500 J

The locomotive engine has the greatest kinetic energy (≈2.56 × 10^6 J).