4th: "The force that the book exerts down on the table is equal to the force the table exerts upward"
Explanation:
Basically, a book on a table is balanced in terms of forces. Gravity is opposed by the table and there are no forces acting to move the book in any direction. If there was a breeze that was not strong enough to move the book, it is because the force of friction is equal to that provided by the breeze.
Power = Net Force x velocity Net force = driving force - force of resistance Driving force = mass x acceleration Acceleration = (final velocity - initial velocity) / time Acceleration = (18 - 0) / 12 = 1.5 m/s² Driving force = 1.5 x 10³ x 1.5 = 2250 N Net force = 2250 - 400 = 1850 Power = 1850 x 18 = 3.33 x 10⁴ Watts
