If there is just one force acting on an object, does its work necessarily result in an increase in kinetic energy? Explain. (Select all that apply.)
1.Yes, when a force does work on an object it always results in an increase in kinetic energy.
2.The work done by the force on the object might result in an increase in kinetic energy.
3.No, if the force is at right angles to a body moving in a circular path, this centripetal force does no work and cannot change the kinetic energy.
4.No, if there is a force component along the line of motion, the force could act opposite to the motion and cause a decrease in kinetic energy.
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The correct options are:
1. Yes, when a force does work on an object it always results in an increase in kinetic energy.
3. No, if the force is at right angles to a body moving in a circular path, this centripetal force does no work and cannot change the kinetic energy.
4. No, if there is a force component along the line of motion, the force could act opposite to the motion and cause a decrease in kinetic energy.
Explanation:
1. When a force does work on an object, it transfers energy to the object, and this energy increase can result in an increase in the object's kinetic energy. This is true in situations where the force is applied in the same direction as the motion of the object.
3. However, if the force is at right angles to the body's motion in a circular path, such as the centripetal force, it does not do work on the object. This is because work is defined as the force applied in the direction of displacement, and in circular motion, the displacement is perpendicular to the force. Therefore, in this case, the work done by the force does not result in a change in kinetic energy.
4. Similarly, if there is a force component along the line of motion, but acting in the opposite direction, it can cause a decrease in the object's kinetic energy. In this scenario, the force is doing negative work, counteracting the object's motion and reducing its kinetic energy.
Therefore, options 1, 3, and 4 explain the different possibilities when a force acts on an object and its impact on the object's kinetic energy.