A ball is projected vertically upward from an initial position (5.0 mathrm{~m}) above the ground (Figure P3.71).

Question:

A ball is projected vertically upward from an initial position $5.0 \mathrm{~m}$ above the ground (Figure P3.71). At the same instant, a cube is released from rest down an ice-covered incline, from a height not necessarily equal to $5.0 \mathrm{~m}$. The two objects reach the ground at the same instant, and both have a final speed of $15 \mathrm{~m} / \mathrm{s}$. What is the angle of the incline?

Data from Figure P3.71