Momentum; bullet block of wood; distance; friction.

In summary, a 10g bullet traveling at 1.5*10^2 m/s hits a 5.5kg wooden block, becoming lodged in it. The block moves 0.15m along the horizontal surface due to the force of friction, which is equal to the force created by the bullet's momentum. The coefficient of friction is 0.25 and the block's acceleration is 0.25m/s^2. The correct answer is 0.015m.
  • #1
General_Sax
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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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  • #2
You made an error while calculating the frictional force
 
  • #3
Oh, I see. Thanks.
 

1. What is momentum and how is it calculated?

Momentum is a measure of an object's motion and is calculated by multiplying its mass by its velocity. The formula for momentum is p = m * v, where p is momentum, m is mass, and v is velocity.

2. How does a bullet's momentum compare to that of a block of wood?

A bullet has a much greater momentum than a block of wood because it has a smaller mass but a significantly higher velocity. This means that the bullet is able to transfer more energy upon impact compared to the wood.

3. How does distance affect momentum?

Distance does not directly affect momentum, but it does affect the velocity of an object. As an object travels a greater distance, its velocity may increase or decrease, which in turn affects its momentum.

4. How does friction impact an object's momentum?

Friction can decrease an object's momentum by slowing it down. When an object is in motion, it experiences resistance from surfaces it comes into contact with, which can reduce its velocity and therefore its momentum.

5. Can momentum be conserved in a closed system?

Yes, according to the law of conservation of momentum, the total momentum of a closed system remains constant. This means that the total momentum before and after an event must be the same, even if individual objects experience changes in momentum.

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