Question

Determine the De Broglie wavelength for a piece of rock that weighs 842 pounds, falling down at the point where it hits the ground after 200 feet.

Answer 1

the speed of the rock when it hits the Surface, is:
\[\Large v = \sqrt {2gd} \]
where \(g\) is gravity, and \(d=200\) feet
the De Broglie wavelength \(\lambda\), is:
\[\Large \lambda = \frac{h}{{\frac{{Wv}}{g}}}\]
where \(W=842\) pounds is the weight of the rock

Answer 2

may i ask why you divided the de broglie equation by g, since it normally is \[\lambda =h/mv\] is it always when an object is falling that you add the g?

Answer 3

also, for the speed of the rock would we just use v=\[\sqrt{2gh}\] or should we take the average and divide by 2 ?

Answer 4

first question:
I have divided by \(g\) since we have:
\(W=mg\), then \(m=W/g\)

Answer 5

second question:
my result above gives the wavelength at the time when the rock hits the earth surface

Answer 6

oh ok! thanks a lot :)

Answer 7

:)