Final answer:
The kinetic energy of a car with a mass of 3250 lb (converted to 1474.19 kg) moving at 55 mph (converted to 24.5872 m/s) is positive, as kinetic energy reflects motion energy and cannot be negative.
Step-by-step explanation:
The kinetic energy (KE) of an object in motion can be calculated using the formula KE = ½mv², where m represents the mass of the object and v represents its velocity. To find the kinetic energy of a car weighing 3250 lb moving at 55 mph, we first need to convert these units into the metric system, which is standard for scientific calculations. The mass in kilograms can be found by converting pounds to kilograms (1 lb = 0.453592 kg), and the velocity in meters per second can be calculated from miles per hour (1 mph = 0.44704 m/s).
After converting units, we can compute the kinetic energy:
- Mass: 3250 lb × 0.453592 kg/lb = 1474.19 kg
- Velocity: 55 mph × 0.44704 m/s/mph = 24.5872 m/s
- KE = ½ × 1474.19 kg × (24.5872 m/s)²
The resulting kinetic energy will be a positive value because kinetic energy is always positive or zero, reflecting the energy associated with motion. It cannot be negative. Hence, the answer choice is B) Positive.