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QOD #103

QOD #103. Calculate the POTENTIAL ENERGY of a ball with a mass of 2 kg, sitting on a ledge 3 meters high. (PE= mgh ) PE=58.8 Joules 2. Calculate the KINETIC ENERGY of that ball as it falls with a velocity of 15m/s. (KE=0.5mv 2 ) KE = 225 Joules Both units are in Joules!. Work. 5-13-14.

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QOD #103

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  1. QOD #103 • Calculate the POTENTIAL ENERGY of a ball with a mass of 2 kg, sitting on a ledge 3 meters high. (PE=mgh) PE=58.8 Joules 2. Calculate the KINETIC ENERGY of that ball as it falls with a velocity of 15m/s. (KE=0.5mv2) KE = 225 Joules Both units are in Joules!

  2. Work 5-13-14 Work – The amount of energy used as a force moves an object over a distance. Ex. Lifting weights • It is not considered work if there is no movement. • Work is measured in Joules (J)

  3. Work Equation W = F d Work (J) = Force (N) x distance (m)

  4. Ex1:A student pushes a desk 2 m using a force of 25 N. How much work does the student do? W = Fd W = 25 N x 2 m W = 50 Joules (J)

  5. Ex2:Jerry drags Tom 3 meters across the floor with a force of 15N. Calculate Jerry’s work. W = Fd W = 15 N x 3 m W = 45 J

  6. Marble Launcher Question: How does the force applied to the marble affect the work done on the marble? Purpose: Calculate work.

  7. IV: force applied to the marble DV: distance marble travels Constants: pressure on lever, size/mass of the marble, Prediction: I think…

  8. The Work Done on a Marble w/ Different Forces Applied

  9. Procedures: • Pull the lever down to the first notch, 3 N. • Place the marble in the launcher. • Make sure everyone is out of the way & ready! Everyone must wear googles! • Push lever & marble will release. • Estimate the distance the marble went. • Someone must be ready to catch the marble & roll it backto the launcher. Record the distance. Jobs: • Marble Launcher • Marble catcher • Distance reader • Recorder

  10. QOD#104 Calculate the amount of work to push a box 20m with a force of 30N. W = Fd W = 30 N x 20 m W = 600 J

  11. Simple Machines Machine – An object that makes doing work easier. Simple Machines – do work using only one movement.

  12. What kind of simples machines are the following?

  13. Goonies Rube Goldberg • https://www.youtube.com/watch?v=SwaTKYJSDaw • Ok-Go! Video • http://www.wimp.com/gomachine/

  14. QOD#105 Identify the simple machines in a pair of scissors.

  15. Identify the simple machines in a bicycle. • Pulley • Wheel & axle • lever

  16. QOD#106 • Calculate the force of an 18kg bowling ball falling off of a building. 2. Calculate the amount of work to push a box 20m with a force of 30N. W = Fd W = 30 N x 20 m W = 600 J 18kg x 9.8m/s² = 176.4 N F = ma

  17. QOD#106 What are the following units for… • m/s • N • km/h north • kg • J • m/s2

  18. 5-14-13 QOD#54

  19. Calculating Work

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