A cart is on a frictionless incline in a uniform gravitational field. Point and point are at the same vertical height above the ground, but is on a steeper section where the incline angle is larger. The reference level is chosen so that at the ground.
Which statement about gravitational potential energy is correct?
- because the component of weight along the incline is larger at .
- because they are at the same height. (correct answer)
- because the incline is steeper at .
- is a vector, so and differ in direction.
Explanation: This question assesses understanding of gravitational potential energy in AP Physics 1. Gravitational potential energy depends solely on vertical height above the reference level, not on path or incline angle. Here, points A and B are at the same height above the ground where U_g = 0, so their potential energies are equal. The steeper incline at A does not affect this, as only vertical position matters. A common distractor, choice A, incorrectly ties energy to the weight component along the incline, but potential is path-independent. To compare potential energies on inclines, measure vertical heights from the reference, ignoring slope variations.