A body of mass $m = 1$ kg slides down a slope of height $h = 5$ m without friction. Find the speed of the body at the bottom of the slope. The acceleration due to gravity is $g = 10$ m/s²; neglect air resistance.
There is no friction, so the kinetic energy at the bottom equals the potential energy at the top:
$$mgh = \frac{mv^2}{2}$$
The mass cancels, hence
$$v = \sqrt{2gh} = \sqrt{2 \cdot 10 \cdot 5} = \sqrt{100} = 10 \text{ m/s}$$
$v = 10$ m/s