# Lab 5forces and motion_handout(1).docx - Phy2053 Forces and...

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Phy2053. Forces and Motion. Phet Simulation Lab Name: Lea Ishkhanova Date: February 19, 2021 Theory. Second Newton’s Law . F net = ma (1) , Kinematics equations. v = v 0 + at (2) Friction force , F r = μ f N (3) Part 1: Motion (No Friction). 1. Click on the Motion tab at the top of the screen. Click on all the buttons in the box in the upper right of your screen: Force Values, Masses, Speed . 2. Put each item listed in the table below on the cart, one at a time. Type 20 N in the Force Box. 3. Using a timing device, time how long it takes to for the object on the skateboard to reach some velocity greater than 7.0 m/s. Record the mass and time on the chart. 4. Calculate the acceleration of the object by using the equation(1) . Calculate the velocity of the object by using the equation (2). 5. Replace the object you tested with the next object on the list. This should reset the speed, etc., but if it doesn’t, click Reset All before you test the next object. This will clear all your buttons, so you will need to recheck those after every trial. Do this before plugging in 20 N each time. Item Mass (kg) Force (N) Time (s) Accelerati on (m/s 2 ) Velocit y (m/s) exp Velocity (m/s) theory % Error Girl 40kg 20 14.32 0.5 7 7.16 2.29% Trash can 100kg 20 35.10 0.2 7 7.02 0.29% Man 80kg 20 28.14 0.25 7 7.035 0.5% 2 Boxes 100k g 20 35.10 0.2 7 7.02 0.29% Refrigerato r 200k g 20 69.55 0.1 7 6.955 0.643% Most Mass Possible: 380k g 20 132.07 0.053 7 6.99971 0.00414%
I have used the formula F = ma in order to calculate the expected acceleration and got all the values for the 5 th column. Then I have used the formula v = v 0 + at to calculate the expected velocities (since v 0 =0): 6. Find the mass of the mystery box, using the mystery box in the simulator keeping the 20 N force, write down in the table the time for specific velocity, always greater than 7.0 m/s. Using the equations 1 and 2 to determine the mystery mass. Data Table 1.b Item Force (N) Time (s) Velocity (m/s) exp Mass (kg) Mystery Box 20 25.14 10 50.28 7. Pile trash can, man and girl. Write down the total mass as an acceptable value of the total mass , apply some
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