4. A.2.5-kg book slides horizontally and falls from a shelf 3.0 m above the floor. How much work does the force of gravity do on the book as it falls 3,0 m? 25J Din 7.35J Do 73.5J Do 1.2.J

To calculate the work done by the force of gravity on the book as it falls, we can use the formula:<br /><br />Work = Force × Displacement × cos(θ)<br /><br />In this case, the force of gravity is acting downward, and the displacement of the book is also downward. Therefore, the angle θ between the force and the displacement is 0 degrees, and cos(0) = 1.<br /><br />The force of gravity acting on the book is equal to its weight, which is the product of its mass and the acceleration due to gravity. The mass of the book is 2.5 kg, and the acceleration due to gravity is approximately 9.8 m/s².<br /><br />So, the force of gravity = mass × acceleration due to gravity<br />= 2.5 kg × 9.8 m/s²<br />= 24.5 N<br /><br />Now, we can calculate the work done by the force of gravity:<br /><br />Work = Force × Displacement × cos(θ)<br />= 24.5 N × 3.0 m × 1<br />= 73.5 J<br /><br />Therefore, the correct answer is C. 73.5 J.