A scientist is exploring the nature of energy and work in two experimental systems.
Experiment 1
She first sets up a system with a ball on an inclined plane, and calculates the potential and kinetic energies of the ball at three positions. She places the ball at position 1, stops the ball after rolling to position 2, and then again allows it to roll to position 3. The measured kinetic and potential energies are shown in the table, along with measurements of the force of friction acting on the ball.
Ball Position Potential Energy Kinetic Energy Force of Friction 1 150 kJ X kJ 0 N 2 75 kJ 75 kJ 0 N 3 X kJ 150 kJ 0 N
Experiment 2
The same scientist then sets up another experiment with the same ball, again at three positions. The ball is provided a slight push, and then allowed to roll down three levels without any additional external input of energy.
She uses the following formulae to calculate the energy levels of the ball:
Potential Energy = Mass of the Ball x Acceleration Due to Gravity x Height of the Ball
Kinetic Energy = (1/2) x Mass of the Ball x (Velocity of the Ball)2
She also measures the internal energy of the ball, a value that she defines as the amount of energy contained in the motion of the molecules that make up the matter of the ball.
Position Potential Energy Velocity Internal Energy 1 A 1 m/s 5 kJ 2 B 5.47 m/s 6 kJ 3 C 10.94 m/s 7 kJ
In Experiment 2, which of the following is most likely true?
A scientist is exploring the nature of energy and work in two experimental systems.
Experiment 1
She first sets up a system with a ball on an inclined plane, and calculates the potential and kinetic energies of the ball at three positions. She places the ball at position 1, stops the ball after rolling to position 2, and then again allows it to roll to position 3. The measured kinetic and potential energies are shown in the table, along with measurements of the force of friction acting on the ball.
| Ball Position | Potential Energy | Kinetic Energy | Force of Friction |
|---|---|---|---|
| 1 | 150 kJ | X kJ | 0 N |
| 2 | 75 kJ | 75 kJ | 0 N |
| 3 | X kJ | 150 kJ | 0 N |
Experiment 2
The same scientist then sets up another experiment with the same ball, again at three positions. The ball is provided a slight push, and then allowed to roll down three levels without any additional external input of energy.
She uses the following formulae to calculate the energy levels of the ball:
Potential Energy = Mass of the Ball x Acceleration Due to Gravity x Height of the Ball
Kinetic Energy = (1/2) x Mass of the Ball x (Velocity of the Ball)2
She also measures the internal energy of the ball, a value that she defines as the amount of energy contained in the motion of the molecules that make up the matter of the ball.
| Position | Potential Energy | Velocity | Internal Energy |
|---|---|---|---|
| 1 | A | 1 m/s | 5 kJ |
| 2 | B | 5.47 m/s | 6 kJ |
| 3 | C | 10.94 m/s | 7 kJ |
In Experiment 2, which of the following is most likely true?