Your 2.85kg physics book rests on a horizontal tabletop.
A. Find the normal force on the book.
B. Suppose you pull up on the book with a 15.0N force, now what's the normal force?
C. Suppose you push down on the book 15.0N Force now what's the normal force?
A) m=2.85 kg, F=?, a=9.8 m/s^2 due to gravity.
F=m*a
F=2.85*9.8=27.9 N
B) Pulling up creates a force against the forces working so.. n-15N.
27.9N-15N=12.9N
C)Pushing up creates a force with the forces already working so.. n+15N
27.9N+15N=42.9N
To answer these questions, we need to understand the concepts of gravitational force and Newton's third law of motion.
A. The normal force is the force exerted by a surface to support the weight of an object resting on it. In this case, the weight of the book is equal to the gravitational force acting on it. The formula for weight is given by the equation:
Weight = mass × acceleration due to gravity
Given:
Mass of the book (m) = 2.85 kg
Acceleration due to gravity (g) = 9.8 m/s²
Using the formula, we can calculate the weight of the book:
Weight = 2.85 kg × 9.8 m/s² = 27.93 N
Therefore, the normal force on the book is equal to the weight of the book, which is 27.93 N.
B. When you pull up on the book with a force of 15.0 N, the normal force will be different. This is because Newton's third law states that every action has an equal and opposite reaction. When you pull up on the book with a force of 15.0 N, the book exerts a downward force of 15.0 N on you. As a result, the normal force will decrease to counterbalance the additional force applied.
To find the new normal force, subtract the applied force from the weight of the book:
New normal force = (Weight of the book) - (Applied force)
New normal force = 27.93 N - 15.0 N = 12.93 N
Therefore, the normal force when you pull up on the book with a 15.0 N force is 12.93 N.
C. When you push down on the book with a force of 15.0 N, the normal force will increase. Applying Newton's third law, the book will exert an equal and opposite force of 15.0 N upward. As a result, the normal force will increase to counterbalance the additional force applied.
To find the new normal force, add the applied force to the weight of the book:
New normal force = (Weight of the book) + (Applied force)
New normal force = 27.93 N + 15.0 N = 42.93 N
Therefore, the normal force when you push down on the book with a 15.0 N force is 42.93 N.