HELP! using graph to find speed

Question

A particle of mass 0.45 kg moves along the x-axis with a potential energy whose dependence on x is shown in the figure.

(can't attach image here search up question above to find the graph)

If the total energy is 17 J, what is the speed of the particle at x = 8.0 m?

Answer 1

Hi Jule!

So they give you the total energy is 17 J. I'm assuming this is total mechanical energy, meaning the sum of the potential and kinetic energy.

First, read the potential energy at x = 8. From the image I found on google, it appeared the potential energy at x = 8 was 0. So, the kinetic energy must equal 17 J.

(1/2)mv² = 17 J, and m = 0.45 kg

Solve for v

v = sqrt (2 x 17 J/0.45 kg) = 8.7 m/s