How Much Energy Is Needed to Drag a Block Over a Distance?

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SUMMARY

The energy required to drag a block over a distance L is determined by the coefficient of friction (μ) between the block and the floor, and the mass (m) of the block. The frictional force opposing the movement is calculated as Fr = μmg. To maintain constant speed, the net force must equal the frictional force, leading to the equation for energy: E = m(a - μg)L. This discussion clarifies that the energy required is equivalent to the work done against friction, not the change in kinetic energy.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Familiarity with the concept of friction and the coefficient of friction (μ)
  • Basic knowledge of work-energy principles
  • Ability to manipulate algebraic equations
NEXT STEPS
  • Study the relationship between friction and motion in physics
  • Learn about work-energy theorem applications in real-world scenarios
  • Explore advanced topics in dynamics, such as acceleration and force analysis
  • Investigate the effects of different surface materials on friction coefficients
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Students in physics or engineering courses, educators teaching mechanics, and anyone interested in understanding the principles of work and energy in relation to friction and motion.

indie452
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Homework Statement



whats the energy required to drag a block a distance L

Homework Equations



coefficiant of friction between block and floor = \mu
density of block = p

force*distance = change in kinetic energy

The Attempt at a Solution



friction acting against movement Fr = \mumg m = mass of block

force in direction of movement F = ma

resultant force = F - Fr = m(a-\mug)

resultant force*L = energy = m(a-\mug)L

i don't think the last step is right though as I am not sure sure that the assumption made that energy required is the same as the change in KE is correct...

help or guidance appreciated
 
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Although not stated as such, I think you are looking for the energy (work) required by a person or machine to just overcome friction and move the block at constant speed (no acceleration).
 

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