A8.1 kg object initially at rest is pushed down a 15.0 m tall hill. what is the speed of the object at the bottom of the hill?

17.14 m/s

Explanation:

We can solve this problem applying the Conservation of Mechanical energy (which is the sum of the kinetic energy and potential energy ), where the total initial mechanical energy must be equal to the total final mechanical energy :

(1)

Being:

(2)

(3)

Where:

is the mass of the object

is the initial velocity (the object was at rest)

is the acceleration due gravity

is the object's initial height or position

is the final velocity

is the object's final height or position

Solving and applying the given conditions:

(4)

(5)

Finding :

(6)

(7)

Finally: