Work, energy and power ppt

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Work, energy and power ppt

  1. 1. Understand the concept of work, energy and power. 1 2 3 4 5 6 Define work, energy and power. Calculate the form of energy by using formula Kinetic Energy and Potential Energy. State the principal of conservation energy. Describe conversion from one form to another form Apply the concept and formula of work, energy and power in solving the related problems. Calculate the efficiency of mechanical system efficiency
  2. 2. Q1: How many steps of batu cave stair? Q2: What is the height of the stair? answer: Q3: How to measure our work or energy when climb a stair? Q4: Who has a big power to delivered up the stair?
  3. 3. Outcomes: Define work, energy and power What does WORK mean to you? Are you doing work when…. Lifting a weights? Walking with a bag grocery in your hand? Completing your homework assignment? Writing essay?
  4. 4. Outcomes: Define work, energy and power WORK is defined as product of the force and displacement of an object in the direction of force. Formula of work is W=Fxs F= Force in Newton s = Displacement in meters. Displacement Unit of work is Joule.
  5. 5. Outcomes: Define work, energy and power Energy is defined as CAPACITY TO DO WORK. SI Unit : Joule (J) Many form. Common one:  Kinetic  Potential  Electric  Chemical  Solar  Nuclear
  6. 6. Outcomes: Define work, energy and power Power is defined as ability to do work. SI Unit : Watt (W) Formula: Power P Work time W t Power second Force displacement time Power Joule Force velocity The Power of body….. Strong and Fast…… (Big Force and small times..)
  7. 7. Let’s twist……
  8. 8. Outcomes: Calculate the form of energy by using formula Kinetic Energy and Potential Energy. Definition : Kinetic energy is energy due to the motion. Formula: KE SI Unit : = ½ m v2 Where: m = mass (kg) v = velocity (ms-1) Joule (J) Kinetic energy Mass, m of F1 car in kg
  9. 9. Outcomes: Calculate the form of energy by using formula Kinetic Energy and Potential Energy. Mass= 624 kg A 624 kg of F1 car is moving at a speed of 150 km/h. Determine the kinetic energy of the car. Given: • Mass = 624 kg • Speed = 150 km 1000m h 1km 1h 3600s 41.67m / s Kinetic energy = ½ m v 2 = ½ x 624 x 41.672 = 541753.34 Joule
  10. 10. Outcomes: Calculate the form of energy by using formula Kinetic Energy and Potential Energy. Definition : Potential energy is energy possessed by an object due to its position or state. Formula: PE SI Unit : =mgh Joule (J) Where: m= mass (kg) g = gravitational acceleration (ms-1) h = height (m) The cat has a POTENTIAL ENERGY at high position.
  11. 11. A load with as mass 5 kg was lifted up by a pulley to the height of 0.8 m for pile work. (Use, g = 9.81 ms-2). What is Potential Energy the load. Solution Ep = m g h = 5 kg x 9.81 x 0.8m = 39.24 J
  12. 12. Outcomes: State the principal of conservation energy . The principle of conservative of energy states that: 1) Energy cannot be created and destroyed 2) Energy can change from one form to another form. 3) Total of energy is constant.
  13. 13. Outcomes: Describe conversion from one form to another form
  14. 14. Outcomes: Describe conversion from one form to another form The roller coaster: A: Potential energy B: kinetic energy C: Potential + Kinetic changes alternately… A C B
  15. 15. ENGINEERING SCIENCE BB101 Total energy is constant.. WORK ENERGY Kinetic Energy Potential Energy Perubahan Tenaga Principle of Conservation of Energy POWER BFZZ, JMSK, PTSB
  16. 16. Outcomes: Apply the concept and formula of work, energy and power in solving the related problems. • If little Nellie Newton lifts her 40kg body a distance of 0.25m in 2 seconds, then what is the power delivered by little Nellie's biceps? Solution • The work done is, W=Fxs = mg x s = 40kg (9.81) x 0.25 m = 100 J • Hence, the power is P = W t = 100 J 2s = 50 Watt 0.25m
  17. 17. Outcomes: Calculate the efficiency of mechanical system efficiency. Mechanical system efficiency • Efficiency is the ratio between the useful power delivered by the motor and the power that you supply to the engine. • Efficiency has no unit and is usually expressed in%. Efficiency of work Work output 100 % Work input Efficiency of power Power output 100 % Power input

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