Question 5 (1 point)
A student walks downstairs to class. Which statement correctly describes the types of energy the student has at the top of the stairs and as she walks down the stairs?
a
kinetic energy at the top of the stairs; kinetic energy as she walks down
b
potential energy at the top of the stairs; kinetic energy as she walks down
c
kinetic energy at the top of the stairs; potential energy as she walks down
d
potential energy at the top of the stairs; potential energy as she walks down
b: potential energy at the top of the stairs; kinetic energy as she walks down
b
potential energy at the top of the stairs; kinetic energy as she walks down
The correct answer is b) potential energy at the top of the stairs; kinetic energy as she walks down.
To understand why this is the correct answer, we need to understand the concepts of kinetic energy and potential energy.
Kinetic energy is the energy an object possesses due to its motion. It depends on both the mass of the object and its velocity. The formula to calculate kinetic energy is KE = 1/2 * mv^2, where m represents the mass of the object and v represents its velocity.
Potential energy, on the other hand, is the energy an object possesses due to its position or state. It can be stored energy that can be converted into other forms of energy, such as kinetic energy. In the case of an object raised at a certain height, the potential energy is due to its position relative to the ground. The formula to calculate potential energy is PE = mgh, where m represents the mass of the object, g represents the acceleration due to gravity, and h represents the height or distance from the ground.
Now let's analyze the scenario in question. When the student is at the top of the stairs, she is at a higher position relative to the ground compared to when she walks down. At this higher position, she has potential energy because of her elevated position. As she walks down the stairs, her potential energy decreases because her height decreases. At the same time, her motion and velocity increase, resulting in kinetic energy. Therefore, the student has potential energy at the top of the stairs and kinetic energy as she walks down. Hence, option b) is the correct answer.