Question

newtons 3rd law of motion: for every action, there is an equal and opposite reaction. if object 1 and object 2 interact, the force exerted by object 1 on object 2 is equal in magnitude but opposite in direction to the force exerted by object 2 on object 1. all forces occur in pairs, thus a single isolated force can not exist.

1. procedures

i. forces and the resulting motion
begin by launching the phet simulation forces and motion, https://phet.colorado.edu/sims/html/forces - and - motion - basics/latest/forces - and - motion - basics_en.html. once running you will land on the home screen with four selection possibilities, net force, motion, friction, and acceleration. feel free to explore the net force portion to understand the results of net force on the motion of an object. we will not be using that portion for this lab.
we will begin with the accerleration selection. in this selection, we will push a variety of objects to investigate the effects of our push and use the motion to determine properties of the system, namely acceleration and mass of the pushed object. once opened you will see a box in the upper right side of the screen. for your convenience, select all 6 boxes. these will show the values and directions of the speeds, forces, masses, and acceleration. move the friction slider to
one\. just below this box is a pause button, hit it. this will prevent the simulation from running as you make your other selections. next to this is the reset button. be warned this resets everything.
what begins in the simulation is your avatar standing next to a wooden crate. below that you will see a selector for setting the force of your push. you will select a force, then hit play. at the same time you will begin a stopwatch and time how long it takes for the box to reach 40 m/s.
as an example, i set the force to 250 n. upon hitting play, i started a timer and the crate wen from 0 m/s to 40 m/s, 8.15 s later. try this. this gives an acceleration of $vec{a}=\frac{delta v}{delta t}=\frac{40}{8.15}=4.91\frac{m}{s^{2}}$. since we applied a force of 250 n to a 50 kg mass, we should obtain an acceleration of $5.0\frac{m}{s^{2}}$. this gives a 2% error for our acceleration. i could also use this acceleration and force to determine the mass that was pushed.
in the same acceleration screen, reset your screen. reset your selections, move friction to none, and pause the simulation. remove the crate from the runway by dragging it down. drag the refrigerator (200 kg) from the bottom left to the runway. select an applied force to push on the appliance. indicate the applied force below.
applied force = _

Explanation:

Step1: Recall Newton's second - law

Newton's second - law is $F = ma$, where $F$ is force, $m$ is mass and $a$ is acceleration.

Step2: Determine the mass and expected acceleration

The mass of the refrigerator $m = 200$ kg, and assume we want to achieve a certain motion similar to the previous example. Let's assume we want to use the expected acceleration value from the example ($a = 5.0\frac{m}{s^{2}}$) for a simple calculation.

Step3: Calculate the force

Using $F=ma$, substitute $m = 200$ kg and $a = 5.0\frac{m}{s^{2}}$. So $F=(200\ kg)\times(5.0\frac{m}{s^{2}})=1000$ N.

Answer:

1000 N