Grigori
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Kinetic energy is a form of energy that an entity or particle possesses due to its motion.

The relation between the object's mass and its speed.

KE = \frac{1}{2} mv^2

The energy contained in an object due to its location is known as potential energy.

PE = mgh , where, m - mass,  g - acceleration due to gravity and h - height.

Law on energy conservation:

Energy can neither be created nor destroyed, but it can be converted from one form to another.

When the object is dropped we initially have only potential energy, which is later transformed to kinetic energy. So according to the law of conversion kinetic energy is equal to potential energy.

KE = PE


Step 1: Determine the velocity of the book

Given that

Mass of a book, m = 1.12 kg

Height of the bookshelf, h = 2.03 m

Acceleration due to gravity g = 9.8. m/s^2

Recall the law on energy conservation: at the beginning, total energy is equal to the end total energy. In this scenario, at the beginning we have only potential energy and at the end only kinetic energy.

PE = KE

mgh = \frac{1}{2}mv^2

v^2=2gh

v=\sqrt{2gh}  

insert the given values in the above equation

v=\sqrt{2*9.8*2.03}

v=\sqrt{39.788}

v=6.3 m/s

Thus, velocity of the book right before the ground  v=6.3 m/s