If a 40 kg rock fell from a cliff and had a speed of 31.3 m/s when it hit the ground, what is its kinetic energy?

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Answer 1 · 2016-12-19T18:38:35

#KE = 1.96xx10^4 J#

To find the rock's kinetic energy we can use the following equation:
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Based on the information you've given me, we know the mass of the rock as well as its velocity:

#m# = 40 kg
#v# = 31.3 m/s

All we have to do is plug in the known values and solve for #KE#:

#KE= 1/2(40kg)(31.3m/s)^2#

#KE = (1.96xx10^4 kgxxm^2)/s^2#

#KE = 1.96xx10^4 J#