# Impulse on a sliding block attched to spring

1. Jan 23, 2009

### jan2905

A 4kg wooden block resting on an icy surface (so friction can be ignored) is attached to a horizontal spring (L=1m, k=100N/kg), which is attached on the other end to a vertical wall. A 2g bullet is fired at a speed of 100m/s into the wooden block, pushing it directly toward the wall. What is the period and amplitude of the resulting oscillations?

f=(1/2pi)sqrt(k/m)

I have no clue?

2. Jan 23, 2009

### m.e.t.a.

Re: Oscillation

A good starting point would be to calculate how much energy the bullet transfers to the spring-block system.

Also (I'm sure it was a typo, but) the spring constant, $k$, can never take the value N/kg. $k$ is a measure of restoring force per unit length of displacement, so the S.I. unit is N/m.

3. Jan 23, 2009

### jan2905

Re: Oscillation

okay... I got T=1.2s and A=45cm ... is this correct?

4. Jan 23, 2009

### LowlyPion

Re: Oscillation

Not sure how you arrived at your amplitude. Your period looks about right, though I would check to see that you rounded correctly.

5. Jan 23, 2009

### m.e.t.a.

Re: Oscillation

Looks good to me. (Just to be pedantic, $\tau$ is closer to 1.3 s than 1.2 s, but you obviously got the correct answer!)