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impstudies

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## Homework Statement

The 2kg head of an axe is moving at 60m/sec when it strikes a log. If the blade of an axe penetrates a 20mm into the log, find the average force it exerts.

m= 2kg

V= 60m/sec

d= 20mm or 0.02m

## Homework Equations

F= pFINAL - pINITIAL / time

t= d/v

## The Attempt at a Solution

m1v1 = axe

m2v2 = log

t = 0.02/60

= 3.33sec

F = [m1v1 + m2v2] - [m1v1 + m2v2] / time

= [(2kg)(60m/sec)+(m2)(0)] - [(2kg)(m2)(0)] / time

= (120 kg.m/sec + m2) / time ?

^ considering the log has 0 velocity? but has no mass given?

I solved for the time then used the impulse formula pFINAL-pINITIAL/time but since there is no mass of the log given I'm baffled because I feel like I'm using the wrong equations. I was lost if I should find the momentum or impulse since the axe makes contact with the log. I'm really bad at physics, your help is so appreciated :(