A Question 20 (1 point) Retake question A student holds her textbook above her head. What is evidence of an energy transfer. motion of the textbook while lifting the textbook change in position of the textbook relative to the classroom floor change in shape of the textbook while sitting above her head a temperature change - heat is being transferred during the lift

The evidence of energy transfer when a student lifts a textbook above her head is the **change in position of the textbook relative to the classroom floor**.<br /><br />Here's why:<br /><br />* **Lifting requires work:** Work is done when a force (the student's muscles) acts on an object (the textbook) to cause a displacement (lifting it upwards). Work is a transfer of energy. The student's muscles transfer chemical energy (from food) into the textbook, giving it gravitational potential energy.<br /><br />* **Gravitational Potential Energy:** When the textbook is higher above the floor, it has more gravitational potential energy. This energy is stored due to its position relative to the Earth. The higher the position, the more potential energy.<br /><br />The other options are incorrect:<br /><br />* **Motion while lifting:** While the textbook is in motion *during* the lift, the motion itself isn't the *evidence* of energy transfer. The change in position resulting from the motion is the evidence.<br />* **Change in shape:** The textbook's shape shouldn't change significantly while being lifted.<br />* **Temperature change:** While some energy might be converted to heat due to friction in the student's muscles, this is a negligible amount and not the primary evidence of energy transfer in this scenario.<br />