Question
8. Two objects were lifted by a machine One object had a mass of 2 kilograms,and was lifted at a speed of 2m/sec The other had a mass of 4 kilograms and was lifted at a rate of 3m/sec a. Which object had more kinetic energy while it was being lifted? b. Which object had more potential energy when it was lifted to a distance of 10 meters?Show your calculation.
Solution
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AllisonVeteran · Tutor for 9 years
Answer
**a. Kinetic Energy Comparison:**<br /><br />Kinetic energy (KE) is calculated using the formula KE = (1/2)mv², where 'm' is mass and 'v' is velocity.<br /><br />* **Object 1:** KE = (1/2) * 2 kg * (2 m/s)² = 4 Joules<br />* **Object 2:** KE = (1/2) * 4 kg * (3 m/s)² = 18 Joules<br /><br />Therefore, **Object 2 (4 kg, 3 m/s)** had more kinetic energy while being lifted.<br /><br /><br />**b. Potential Energy Comparison:**<br /><br />Potential energy (PE) is calculated using the formula PE = mgh, where 'm' is mass, 'g' is the acceleration due to gravity (approximately 9.8 m/s²), and 'h' is height.<br /><br />* **Object 1:** PE = 2 kg * 9.8 m/s² * 10 m = 196 Joules<br />* **Object 2:** PE = 4 kg * 9.8 m/s² * 10 m = 392 Joules<br /><br />Therefore, **Object 2 (4 kg)** had more potential energy when lifted to a height of 10 meters.<br />
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