Momentum; bullet block of wood; distance; friction.

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SUMMARY

The discussion centers on a physics problem involving momentum and friction, specifically calculating the distance a wooden block moves after being struck by a bullet. The bullet, weighing 10g and traveling at 150 m/s, embeds itself in a 5.5kg block, with a friction coefficient of 0.25. The correct calculation shows that the block moves 0.15m, while the book states 0.015m, indicating a likely misprint in the textbook. The key equations used include momentum (p = mv) and the relationship between force and distance.

PREREQUISITES
  • Understanding of basic physics concepts such as momentum and friction.
  • Familiarity with the equations of motion, particularly d = 0.5*a*t^2.
  • Knowledge of how to calculate forces using F = ma.
  • Ability to manipulate units and convert between mass and weight.
NEXT STEPS
  • Review the principles of conservation of momentum in inelastic collisions.
  • Study the effects of friction on motion, particularly in horizontal surfaces.
  • Learn how to apply Newton's second law (F = ma) in practical scenarios.
  • Explore common errors in physics calculations and how to avoid them.
USEFUL FOR

Students studying physics, educators teaching mechanics, and anyone interested in understanding the principles of motion and friction in real-world applications.

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Homework Statement


A 10g bullet is traveling at a speed of 1.5*10^2 m/s parallel to a horizontal surface when it strikes a 5.5kg wooden block. If the bullet becomes lodged in the block, how far will the block move along this surface? The coefficient of friction between the block and the surface is 0.25.


Homework Equations


p = F(delta)T

d = 0.5*a*t^2

p = mv

The Attempt at a Solution



p = (0.010kg)*(150m/s) = 1.5 kg*m/s
Ff = (0.25)(5.51) = 1.3775

Ff = Fp // when the force created by momentum is equal to the force of friction.

Ff = p / (delta)t

(delta)t = p / Ff

(delta)t = 1.0889s

a = F/m

a = p / t*m

a = 0.25m/s^2

d = 0.5*0.25*(1.0889)^2

d =0.15m

The answer in the book is: 0.015m. Did I make a mistake somwhere or is the answer a misprint?
 
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You made an error while calculating the frictional force
 
Oh, I see. Thanks.
 

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