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Hi all,

I have been attempting the following question, could you check my answers /method please :)

A pile is driven into the ground by a hammer of mass 500Kg's dropped from a height of 4 meters. The mass of the pile is 40Kg's and the average resistance of the ground penetration is 45K Newtons.

1. Calculate the velocity and Kinetic energy of the hammer prior to the impact with the pile.

I used the formula v^2=u^2+2as to give me 8.8589 m/s. For the KE I used 1/2mv^2 giving me 19620 Joules.

2. Calculate the velocity and Kinetic energy of the hammer/pile combination immediately after the impact.

By using the momentum of pile and hammer after impact = the momentum before impact. (Let v1 = Common velocity after impact)

I got (500KG + 40KG)v1 = 500KG x 8.8589m/s (velocity before)

By transposing I get v1 = 8.203m/s.

Now for kinetic energy I used 1/2mv^2 again but this time I used the total mass of pile & hammer and the comman velocity after impact to give me 18168J.

3. Calculate the distance for which the pile penetrates the ground??

I am really struggling with this question, cannot seem to find a formula to link the distance driven into the ground?? Can anyone help?

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# A pile driven into ground using a hammer question

**Physics Forums | Science Articles, Homework Help, Discussion**