- #1

emily081715

- 208

- 4

## Homework Statement

You shoot a 0.0050-kg bullet into a 2.0-kg wooden block at rest on a horizontal surface (Figure 1) . After hitting dead center on a hard knot that runs through the block horizontally, the bullet pushes out the knot. It takes the bullet 1.0 ms to travel through the block, and as it does so, it experiences an x component of acceleration of -4.9 × 105 m/s2. After the bullet pushes the knot out, the knot and bullet together have an x component of velocity of +10 m/s. The knot carries 10% of the original inertia of the block.

What is the initial velocity of the bullet?

## Homework Equations

Conservation of momentum equation

p

_{i}=p

_{f}

m1v1i+m2v2i=m1v1f+m2v2f

## The Attempt at a Solution

v1f= (0.2)(10)+0.005(10)/ 0.005

=410m/s

the 0.2 came from the 10% of 2kg wooden block (knot)

this answer is incorrect but i am unsure where my error is and what simple step i have missed