Please use the link for this lab:https://phet.colorado.edu/sims/html/forces-and-motion-basics/latest/forces-and-motion-basics_en.html

Click on the link and you will find four simulations. You will use the 2^nd simulation from the left which is "Motion". Now click on the simulation "Motion and you will see a skateboard, objects with different masses and a robot. The masses can be dragged onto the skateboard and the robot can push the skateboard. The skateboard has no friction with the ground. If the skateboard is pushed and give it a velocity, it continuously moves with that speed and never stops.

The robot pushes the skateboard as long as you hold down the mouse. Notice that an arrow appears next to the skateboard called "applied force": this is the push that the robot makes on the skateboard.

STEP 1:

Checkmark the Force, Values, Masses, and Speed in the simulation which is located at the upper right corner of your computer screen. Now you can read the values of the masses and speeds of the skateboard.

STEP 2:Drag a small mass, for example, 40kg, onto the skateboard and give them a little push by the robot so that the skateboard and the mass move with a speed between 5m/s and 10m/s. Now record the mass and the speed.

Mass on the board: Speed:

STEP 3:

Don't disturb or change the motion of the skateboard. Now wait for a few minutes and see if there is any change in speed. Does the speed change?

Yes No

STEP 4:

Now gently drag another mass hold it just above the first mass on the skateboard for a few second and then drop it on the first mass and wait for a few minutes. Record the mass on the board and its speed.

Mass on the boar: Speed:

Note: When you hold the second mass above the skateboard the speed of the second mass reaches to the speed of the skateboard and they move with the same speed. The speed of the second mass relative to the skateboard is zero.

STEP 5:

Now gently drag another mass onto the skateboard and record the mass and speed.

Mass on the skateboard: Speed:

STEP 6:

Write down all the masses and their respective speeds in the table below:

Mass	Speed

Nowwrite down a few words or comments about the findings of the experiment. What did you understand from this experiment?

STEP 7:

Now remove all the masses from the skateboard. Drag the smallest mass onto the board and give it a medium push so that it starts moving with a speed between 20m/s and 30m/s. Wait for a few minutes and record the mass and speed.

Mass: Speed:

STEP 8:

Repeat STEP 3 to STEP 6 and write down all the masses and speeds in the table bellow:

Mass	Speed

What is the purpose and main idea of the lab?

Write down a real-world example which can better explain the main idea of the lab.