Posted by **sarah** on Sunday, June 14, 2009 at 1:40pm.

a pile drive has a 413 kg block that is lifted 1.4m and then dropped onto the pile being driven into the ground. suppose that it takes 24ms to stop when it hits the pile. what is the average force exerted on the pile by the pile driver?

- physics -
**drwls**, Sunday, June 14, 2009 at 2:29pm
Force x distance driven =

Potential energy of the lifted weight

= (413)(9.8)(1.4) J

The distance X that the pile gets driven each time is (1/2)*(pile impact velocity)*time

The impact velocity of the pike is

V = sqrt(2gH)

Compute V, X, and then solve for the force.

- physics -
**drwls**, Sunday, June 14, 2009 at 3:42pm
I just realized that this problem can be solved more directly using momentum considerations. The answer should be the same.

(Force)(stopping time)

= momentum at impact = M V

F = M V/(0.024 s)

V = sqrt(2gH), as before

- physics -
**alicia**, Saturday, July 2, 2011 at 7:11pm
A spelunker (cave explorer) drops a stone from rest into a hole. The speed of sound is 343 m/s in air, and the sound of the stone striking the bottom is heard 3.87 s after the stone is dropped. How deep is the hole?

## Answer This Question

## Related Questions

- Physics - Suppose the 480 lb pile driver that drops 20 ft drives the pile 2 in...
- Physics - Suppose the 480 lbs pile driver that drops 20 ft drives the pile 2.0 ...
- Physics - Suppose the 480 lbs pile driver that drops 20 ft drives the pile 2.0 ...
- physics. - : When the mass hits the pile, it has kinetic energy. This energy is ...
- Physics - a 2199 kg pile driver is used to drive a steel beam into the ground. ...
- Timerate problem(calculus) - Sand is being dropped at the rate 10 metercube/min ...
- physic - A 2,300-kg pile driver is used to drive a steel I-beam into the ground...
- Related rates - Sand is being dropped at the rate of 10 cubic meter per minute ...
- Science Physics - A pile driver falls a distance of 1.75 m before hitting a pile...
- calculus word problem - a conveyor belt pours gravel into a pile at a rate of 20...

More Related Questions