The first graph shows the potential energy U(x)for a particle moving on the x axis.Which of the following five graphs correctly gives the force F exerted on the particle?
A)I
B)II
C)III
D)IV

Question

The first graph shows the potential energy U(x)for a particle moving on the x axis.Which of the following five graphs correctly gives the force F exerted on the particle? 
A)I 
B)II 
C)III 
D)IV

Quizplus · Accepted Answer

The force on the particle is given by the negative gradient of the potential energy (i.e. F = -dU/dx). This means that as the potential energy increases (i.e. as the particle moves away from the minimum), the force becomes more negative, pulling the particle back towards the minimum. This behavior is only exhibited by graph D.

The First Graph Shows the Potential Energy U(x)for a Particle