How did kinetic energy and potential energy compare to the total energy during the
motion without friction? What about when friction was turned on?
To understand how kinetic energy, potential energy, and total energy compare during motion with and without friction, let's break it down and consider each situation separately:
Motion without friction:
In the absence of friction, the total mechanical energy of a system is conserved. This means that the total energy remains constant throughout the motion. It is the sum of kinetic energy and potential energy.
- Kinetic energy (KE): Kinetic energy is the energy possessed by an object due to its motion. It depends on the mass (m) and velocity (v) of the object and is given by the formula KE = 1/2 * m * v^2. This energy increases as the object's speed increases.
- Potential energy (PE): Potential energy is the energy stored in an object due to its position or configuration within a force field. The most common type is gravitational potential energy (GPE), which depends on the mass (m), height (h), and acceleration due to gravity (g). The formula for GPE is PE = m * g * h. This energy increases as the object is lifted to higher heights.
When there is no friction, as the object moves, its kinetic energy increases as it gains speed, and potential energy decreases as it loses height (if applicable). However, the sum of the kinetic energy and potential energy remains constant, resulting in a constant total energy throughout the motion.
Motion with friction:
When friction is introduced, kinetic energy is affected. Friction acts as a resistive force that opposes motion, slowing down the object. As the object experiences friction, some of its kinetic energy is converted into other forms of energy, such as heat or sound.
As a result, the object's kinetic energy decreases over time, leading to a decrease in total mechanical energy during the motion. The potential energy may still change depending on the object's position or configuration, but it is not directly affected by friction.
In summary, without friction, the total energy (the sum of kinetic energy and potential energy) remains constant during motion. However, when friction is present, the kinetic energy decreases, causing a decrease in total mechanical energy.