posted by Chelsea .
An object with a mass of 3.4 kg is originally at rest on a horizontal, frictionless surface frictionless which is at the top of a frictionless incline with a length of 6 meters which is inclined at 28.9 degrees. Someone's hand applies a force to the object over some displacement and the object travels down the incline, across a horizontal frictionless surface and then up another frictionless incline which is inclined at 69.3 degrees. It travels 16 meters up the second incline before it stops. How much energy was given to the object from the person's hand in Joules?
E=PE2-PE1=m•g•h2 -m•g•h1 =
=m•g•s2•sinβ- m•g•s1•sinα =
=m•g•( s2•sinβ -s1•sinα )=
=3.5•9.8•(16•sin69.3 - 6•sin28.9) =402 J