Question

When an object is solely under the influence of conservative forces, the sum of its kinetic and potential energies does not change. True or False

Answer 1

Answer:

True

Explanation:

- A conservative force is a force whose work done does not depend on the path taken, but only on the final and starting point.

- The mechanical energy of an object is defined as the sum of the kinetic energy (K) and the potential energy (U): E = K + U

- The law of conservation of energy states that, in case only conservative forces are acting on the object, the mechanical energy of the object E is conserved

- In case non-conservative forces are acting on the object, the mechanical energy is no longer constant. An example of non-conservative force is the force of friction: when the force of friction is acting on a car in motion, the car is slowed down by the effect of the force, losing some of its kinetic energy, K. If the car is travelling on a flat road, then its potential energy U does not change: this means that the mechanical energy of the car, E, is decreasing, so it is no longer conserved.