January 15th, 2019, 06:53 AM  #1 
Senior Member Joined: May 2014 From: Allentown PA USA Posts: 113 Thanks: 6 Math Focus: dynamical systen theory  How is this answer possible?
Dear My Math Forum: A ball of clay falls to the ground from a height of 15 meters. It is in contact with the ground for 0.020 seconds before coming to rest. What is the average acceleration of the clay during the time it is in contact with the ground? The correct answer to this problem is 858 meters/second^2. Could someone please provide me with a stepbystep demonstration as to how this answer was arrived at? Thank you. 
January 15th, 2019, 07:17 AM  #2 
Math Team Joined: Jul 2011 From: Texas Posts: 3,031 Thanks: 1620 
$\bar{a} = \dfrac{\Delta v}{\Delta t}$ $\Delta v$ = (rest velocity)  (final velocity at the start of impact) note ... $v_f^2 = v_0^2  2g \Delta y \implies v_f = \sqrt{0  2g(15)} = \sqrt{30g}$ $\bar{a} = \dfrac{0  (\sqrt{30g})}{0.02}$ using $g = 9.81 \, m/s^2$ yields the average acceleration given. 

Tags 
answer 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Does Anyone answer to this?  thomas2608  Algebra  3  December 1st, 2014 06:55 PM 
How did they get this answer?  SeanDaniel  Algebra  7  November 27th, 2014 02:17 PM 
numeric entry problem with answer..but I think the answer is  rage  Algebra  2  September 14th, 2012 09:27 PM 
0 is the answer but how do i get there  rk183  Algebra  2  October 14th, 2010 10:28 PM 
No one can seem to answer this?  MathBane  Algebra  1  October 9th, 2009 09:53 AM 