Final answer:
To find the speed of the box when it has fallen 2.5 m, we can use the concept of conservation of energy. The speed of the box is 7.9 m/s.
Step-by-step explanation:
To find the speed of the box when it has fallen 2.5 m, we can use the concept of conservation of energy. Initially, the box is at rest and all the potential energy is converted into kinetic energy. The potential energy is given by mgh, where m is the mass of the box, g is the acceleration due to gravity, and h is the height. The kinetic energy is given by (1/2)mv^2, where v is the velocity. Equating the two and solving for v, we get:
v = sqrt(2gh)
Plugging in the values, we have:
v = sqrt(2 * 9.8 m/s^2 * 2.5 m)
v = 7.9 m/s