Question

a body is dropped from a height h. By using the concept that during the fall the body's total mechanical energy remains constant, find its speed when the body is at height h/4. (ignoring air resistance).

Answer 1

Given that the body is dropped from a height , then the body is under the force of gravity.

Its initial speed is 0 since it is under free fall.

We also have the height which in our case is h/4

We will use the following kinematics equation:

v² = u² + 2gs

In our case :

S = h/4

u = 0

g = 10

Doing the substitution we have :

v² = 0 + 2 × 10 × h/4

v² = 0 + 5h

v = √5h

The speed at h/4 is therefore :

√5h