Momentum and stopping distance

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SUMMARY

In the discussion, it is established that when two objects with different masses but the same momentum are stopped using the same retarding force, the heavier object will stop in a shorter distance. This conclusion is derived from the relationship between momentum (p=mv) and kinetic energy (KE=1/2m(v^2)). The key equations discussed include the change in kinetic energy (change in KE=fd) and the derived formula for kinetic energy in terms of momentum (KE=p^2/2m). The analysis clarifies that a greater mass results in a smaller kinetic energy, leading to a shorter stopping distance.

PREREQUISITES
  • Understanding of momentum (p=mv)
  • Knowledge of kinetic energy equations (KE=1/2m(v^2))
  • Familiarity with the concept of retarding force
  • Basic algebra for manipulating equations
NEXT STEPS
  • Study the relationship between momentum and kinetic energy in greater detail
  • Explore the implications of retarding force on stopping distances
  • Learn about the conservation of momentum in different mass scenarios
  • Investigate real-world applications of these principles in vehicle safety
USEFUL FOR

Students studying physics, educators teaching mechanics, and anyone interested in understanding the dynamics of motion and stopping distances.

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Homework Statement



Two objects have different masses, but the same momenta. If you stop them with the same retarding force, which one will stop in the shorter distance. The heavier or lighter one? Or will both have the same distance?




Homework Equations





The Attempt at a Solution



Wouldn't the heavier one take more force to stop it, thus leading to a greater distance? However, the correct answer is that the heavier one will stop in the shorter distance. Explain, thanks!
 
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What's the equation which relates momentum to mass and velocity?
 
retarding force X distance moved = change in kinetic energy.
Can you find the relation between momentum and kinetic energy?
 
p=mv

change in KE=fd

KE=1/2m(v^2)


KE=p^2/2m

So basically, the greater the mass, the smaller the KE. And the smaller the KE, the smaller the distance. ok...thanks.
 

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