Falling brick speed - equation needed

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SUMMARY

The discussion centers on calculating the speed of a falling brick after descending 20 meters, starting from rest (U=0). The correct equation to use is derived from the principles of conservation of energy, specifically the kinematic equation v² = u² + 2as. Given that the initial speed (u) is zero and the acceleration (a) is due to gravity (approximately 9.8 m/s²), the final speed (v) is calculated to be 19.8 m/s.

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I have a question in my work book that I cannot solve as I can't find the correct equation. The question is:

What speed will the brick have after falling through a distance of 20 metres? U= at rest. There are no other constants given. What equation would I use to solve this problem?

(I have looked in the back of the book and the answer is:19.8 m/s)

Thanks,
Cat.
 
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Think conservation of energy. Compare the initial and final energies at each state and equate them.
 
v**2=u**2+2as
 
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