# Newton's Thrid Law Question

## Homework Statement

I have a mass of 65kg. If I jump off a 120-cm-high table, how far toward me does Earth move during the time i fall?

F=ma

## The Attempt at a Solution

P.S

kuruman
Homework Helper
Gold Member
What is the force that you exert on the Earth? Knowing this force, can you calculate the Earth's acceleration?

ok, i had another try of this question and i went W=mg which is 68 * 9.8 i get the force 666.4N then what should i do next?

kuruman
Homework Helper
Gold Member
ok, i had another try of this question and i went W=mg which is 68 * 9.8 i get the force 666.4N then what should i do next?
If 666.4 N is the force that the Earth exerts on you, what the force that you exert on the Earth?

the same because of Newton's Third Law, so i found the acceleration by doing the following:
Mass of Earth is 5.97 * 10^24 (according to the book)

637 = (5.97 *10^24)a
a=1.06*10^-22 m/s^2

now how do i find how far toward me does Earth move during the time i fall?

kuruman
Homework Helper
Gold Member
the same because of Newton's Third Law, so i found the acceleration by doing the following:
Mass of Earth is 5.97 * 10^24 (according to the book)

637 = (5.97 *10^24)a
a=1.06*10^-22 m/s^2

now how do i find how far toward me does Earth move during the time i fall?

How many seconds does it take you to fall 1.20 m to the surface of the Earth with an acceleration of 9.8 m/s2? In that same amount of time the Earth "falls" towards you with an acceleration of 1.06x10-22 m/s2. Use the kinematic equation to find the distance.

thanks i know how to do it now.