Solving a Momentum Problem: Bullet-Block System with Spring Compression

  • Thread starter Thread starter mohamud3917
  • Start date Start date
  • Tags Tags
    Momentum
AI Thread Summary
To determine the bullet's velocity at impact with the block, the discussion emphasizes analyzing the problem in two parts: the collision and the subsequent spring compression. The conservation of momentum applies during the collision, while the energy stored in the spring is relevant after the collision. The force exerted on the spring can be calculated using F = kx, but the key is to relate the kinetic energy of the bullet-block system to the potential energy stored in the spring. By understanding these conservation principles, one can derive the bullet's initial velocity. The approach focuses on energy and momentum conservation to solve the momentum problem effectively.
mohamud3917
Messages
11
Reaction score
0
A 11.0-g bullet is fired horizontally into a 108 g wooden block that is initially at rest on a frictionless horizontal surface and connected to a spring of constant 154 N/m. If the bullet-block system compresses the spring by a maximum of 76.0 cm, what was the velocity of the bullet at impact with the block.

what i did first was i set F=kx to find the force the bullet block system applied to the spring.

after solving for F, i couldn't find a way to relate force to the momentum equation
m1v1i=(m1+m2)vf
 
Physics news on Phys.org
mohamud3917 said:
what i did first was i set F=kx to find the force the bullet block system applied to the spring.
Instead of worrying about the force, consider the energy stored in the spring.
 
ok so how do i set it up
 
Think of the problem as having two parts:
(1) The collision itself. What's conserved during the collision?
(2) The compression of the spring after the collision. What's conserved here?
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Conservation of momentum in a bullet-block-spring system
Replies
6
Views
3K
Distribution of Energy when work is done on a system of 2 masses connected by a spring
Replies
17
Views
2K
Problem with when to use Force and Energy. What compresses spring/
Replies
3
Views
1K
A bullet pushing a knot out of a wood block
Replies
13
Views
3K
A block of mass m is dropped onto the top of a vertical spring....
Replies
8
Views
5K
Momentum problem -- Two bullets fired into a block
Replies
7
Views
2K
Having trouble on this energy and momentum question
Replies
4
Views
4K
Kleppner - blocks and a compressed spring
Replies
3
Views
3K
Ballistic Spring System Problem
Replies
3
Views
2K
Newton's law problem: Pushing 2 stacked blocks on a horizontal table
Replies
13
Views
3K

Hot Threads

Recent Insights

Back
Top