A 1-kg book is at rest on a desk. Determine the force the desk exerts on the book.
If the book is "at rest," wouldn't the desk have to exert an equal force?
I hope this helps. Thanks for asking.
To determine the force the desk exerts on the book, we need to consider Newton's second law of motion, which states that the force acting on an object is equal to the mass of the object multiplied by its acceleration.
In this case, the book is at rest, which means its acceleration is zero. Therefore, according to Newton's second law, the net force acting on the book must also be zero.
Since the only forces acting on the book are its weight (due to gravity) and the force exerted by the desk, we can conclude that the force exerted by the desk on the book must be equal in magnitude and opposite in direction to the weight of the book.
The weight of an object is given by the formula:
weight = mass × acceleration due to gravity
In this case, the mass of the book is 1 kg, and the acceleration due to gravity is approximately 9.8 m/s² on Earth.
So, the weight of the book is:
weight = 1 kg × 9.8 m/s² = 9.8 Newtons
Therefore, the force exerted by the desk on the book is also 9.8 Newtons, but in the upward direction to balance the weight of the book.