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Homework Statement
Man who weighs 915 N stands on a flatcar that weighs 2640 N as it rolls at 16.0 m/s in positive x direction. No friction. Man runs in negative x direction at 53 m/s relative to the flatcar. What is the resulting increase in speed of flatcar?
Homework Equations
Velocity(man, flatcar) = Velocity(man, ground) + velocity(ground, flatcar)
F(g) = ma(g)
m(1i)v(1i) + m(2i)v(2i) = m(1f)v(1f) + m(2f)v(2f)
The Attempt at a Solution
I divided weight by 9.81 to arrive at mass(man) = 93.3 kg and mass(flatcar) = 269 kg. I then found the velocity of the man relative to the ground to be -37 m/s. Using conservation of momentum, I found that the final velocity of the flatbed to be 34.4 m/s. This led to an increase of 18.4 m/s for the flatbed.
93.3(16) + 269(16) = 93.3(-37) + 269v(flatbed, final)