A model rocket with a mass of 2.7kg is launched straight up from the ground at a speed of 110m/s. What is the rocket's mechanical energy when it takes off?

1 Answer
Nov 15, 2015

Answer:

I found #16kJ#

Explanation:

We can choose the firing position as "zero" for Gravitation Potential Energy (height #h# zero);
Mechanical energy at this point will be given as the contribution of Potential and Kinetic energy:
#E_("mec")=U+K=mgh+1/2mv^2#
but #U=0# and so:
#E_("mec")=0+K=K=1/2mv^2=1/2(2.7)(110)^2=16,335J~~16kJ#