what is the potential energy of the cart relative to the ground at A ?

Question

a roller coaster of mass 396 kg starts stationary at pointA, where H1=37.9 m and a while later is at point B, where H2 is 9 m. the acceleration of gravity is 9.8 m/s^2. what is the potential energy of the cart relative to the ground at A ? and what is the speed of the cart at B, ignoring the effect of friction ?

Answer 1

The potential energy w/r/t the ground at point A is

g*m*H1

=9.81*396*37.9
147 kJ

Using potential energy to find the speed
g*m*(H1-H2)=.5*m*v^2
v=sqrt(2*9.81*28.9)
=23.8 m/s

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