Speed or turning point using energy

[DrClaude]

We go for correct answers here. Not answers that we think the answer key thinks are correct.

Have you calculated the result? Because I get an answer that is compatible with the answer key.

 

[jbriggs444]

Have you calculated the result? Because I get an answer that is compatible with the answer key.

I rechecked and you are correct.

Edit: Thinking back, I'd double-dipped on the 20J of initial potential energy, both adding it to the initial total energy and subtracting it from the potential barrier left to overcome, leaving just enough energy to make it past.