1)The Earth exerts an 710 N gravitational force
on a man.
What force does the man exert on the
Earth?
Answer in units of N
2)If a book is sitting on a table, the force of
gravity pulls it down.
Why doesn’t it fall?
Is it because The table is pushing up on it with a force
equal to the weight of the book.
For every force there is an equal and opposite force.
I agree with #2 and I bet you can figure out #1 based on the above.
Thanks
You are welcome.
1) According to Newton's third law of motion, for every action, there is an equal and opposite reaction. In this case, the Earth exerts a gravitational force of 710 N on a man. Therefore, the man also exerts an equal but opposite force on the Earth.
Therefore, the force that the man exerts on the Earth is also 710 N.
2) Yes, the book doesn't fall because the table is pushing up on it with a force equal to the weight of the book. The force of gravity pulls the book downward, while the table exerts an upward force called the normal force. As long as the normal force is equal to or greater than the weight of the book, the book remains in equilibrium and does not fall. This is an example of Newton's second law, where the forces are balanced, resulting in no acceleration.