Question 7 (1 point)
The diagram shows a simple pendulum.
Neglecting friction, what happens to the total mechanical energy as the pendulum swings from position A to position B?
a
It increases.
b
It decreases.
c
It is not conserved.
d
It remains the same.
d) It remains the same.
The correct answer is d) It remains the same.
In a simple pendulum, the total mechanical energy is the sum of its kinetic energy (KE) and potential energy (PE). As the pendulum swings from position A to position B, the height (potential energy) decreases, while the speed (kinetic energy) increases. However, the total mechanical energy remains constant because the decrease in potential energy is exactly balanced by the increase in kinetic energy. This is due to the conservation of energy principle, which states that energy can neither be created nor destroyed, but only transferred from one form to another. Therefore, the total mechanical energy of the pendulum remains the same throughout its motion, neglecting the effects of friction.
To answer this question, we need to understand what mechanical energy is and how it relates to a simple pendulum.
Mechanical energy is the sum of kinetic energy (the energy of motion) and potential energy (the energy resulting from an object's position or condition). In the case of a simple pendulum, the mechanical energy is primarily in the form of potential and kinetic energy.
When the pendulum is at position A, it is at its highest point on one side of its swing. At this position, the pendulum has maximum potential energy and minimum kinetic energy since it is momentarily at rest.
As the pendulum swings down to position B, potential energy is converted into kinetic energy. At position B, the pendulum has reached its lowest point on the other side of its swing. At this position, the pendulum has minimum potential energy and maximum kinetic energy since it is moving with its maximum speed.
Since we are neglecting friction, energy is conserved in this system. This means that the total mechanical energy remains constant throughout the pendulum's motion. Therefore, the correct answer is option (d) It remains the same.
To arrive at this answer, you can use the principle of conservation of mechanical energy, which states that the total mechanical energy of a system remains constant as long as no external forces (such as friction) act on it.