What is the kinetic energy of an object with a mass of # 5 kg# that has been in freefall for # 4 s#?

1 Answer
Apr 8, 2016

Answer:

About #4000J#

Explanation:

In freefall, I assume acceleration due to gravity, #g# is #10ms^-2#.

#g=(v-u)/t#
We need to find the final velocity #v#. We know that the initial velocity #u=0# and #t=4s#
#g*t=v#
#10ms^-2*4s=40ms^-1#

Kinetic energy is #1/2mv^2=1/2*5kg*(40ms^-2)^2=4000J#