Procedure: 1. Open phet Colorado link : https ://phet .colorado .edu /sims /html /forces -and -motion - basics /latest /forces -and -motion -basics_en .html 2. and choose Net Force. 3. Show sum of forces , values and speed . 4. Using Newton's Law, calculate and find the mass. 5. Show results in table. Force (Blue ) Force (Red ) Acceleration ( constant Mass = F/a 50 200 100 150 150 100 200 50