Why is it easier to move a box already in motion than to start moving ...
The force required to overcome static friction (to start moving) is greater than the force required to overcome sliding friction (to keep it moving).
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Why is it easier to move a box already in motion than to start moving ...
Understanding Friction in Motion
Moving a box requires overcoming forces that resist its movement. The primary reason it is easier to move a box already in motion than to start moving it is due to the differences in frictional forces involved.
Types of Friction
- Static Friction: This is the friction that must be overcome to start moving an object at rest. It is usually higher than kinetic friction.
- Kinetic Friction: Once the object is in motion, it experiences kinetic friction, which is generally lower than static friction.
Why is Option B Correct?
- Less Static Friction: When an object is stationary, static friction acts to keep it at rest. This force can be significant and varies depending on the materials in contact. It requires a greater applied force to overcome this static friction and initiate movement.
- Once in Motion: Once the box is moving, it transitions to kinetic friction. Kinetic friction is easier to overcome because it is less than static friction.
Implications of Kinetic Energy
- Energy Considerations: An object in motion has kinetic energy, which means it will continue to move unless acted upon by another force. Thus, once the box is in motion, it requires less energy to maintain that motion compared to the energy needed to start it.
Conclusion
In summary, the reason it is easier to move a box already in motion than to start moving it is primarily due to the lower kinetic friction that acts on a moving object compared to the higher static friction that must be overcome to initiate movement.