Physics Lesson 13 - Mechanical Work 2 PDF

WORK & ENERGY MR. JEROME MORALES MR. CARL FERMIL AGUINALDO GRADE 10 PHYSICS TEACHERS Copyright © 2022 Saint Jude Catholic School, Manila  ACTIVITY BRING ME! Copyright © 2022 Saint Jude Catholic School, Manila DIRECTIONS The teacher will ask the stud...

WORK & ENERGY MR. JEROME MORALES MR. CARL FERMIL AGUINALDO GRADE 10 PHYSICS TEACHERS Copyright © 2022 Saint Jude Catholic School, Manila  ACTIVITY BRING ME! Copyright © 2022 Saint Jude Catholic School, Manila DIRECTIONS The teacher will ask the students to bring random objects at home and show it in the camera. First student to show the object wins a recitation chip. Copyright © 2022 Saint Jude Catholic School, Manila BRING ME ITEM #1 ONE PESO COIN Copyright © 2022 Saint Jude Catholic School, Manila BRING ME ITEM 2 PAIR OF SOCKS Copyright © 2022 Saint Jude Catholic School, Manila BRING ME ITEM 3 PHYSICS NOTEBOOK Copyright © 2022 Saint Jude Catholic School, Manila BRING ME ITEM 4 CHEMISTRY TEXTBOOK (GLENCOE) Copyright © 2022 Saint Jude Catholic School, Manila BRING ME ITEM 5 BIOLOGY TEXTBOOK (GLENCOE BIOLOGY) WITH CHEMISTRY TEXTBOOK (GLENCOE) Copyright © 2022 Saint Jude Catholic School, Manila PROCESSING QUESTION What have you noticed with the order of the items asked of you to bring to the camera? Copyright © 2022 Saint Jude Catholic School, Manila PROCESSING QUESTION What are the steps that you did to bring the books in front of the camera? (Be as detailed as possible) Copyright © 2022 Saint Jude Catholic School, Manila PROCESSING QUESTION Can you say that the FORCE you exerted caused the items to be DISPLACED from where they are from to where they are now? Copyright © 2022 Saint Jude Catholic School, Manila  LEARNING OBJECTIVES Identify situations in which work is done and in which no work is done Differentiate potential and kinetic energy and their practical applications Identify and explain the factors that affect potential and kinetic energy Solve problems involving work and energy State and explain the work-energy theorem and give examples for each Copyright © 2022 Saint Jude Catholic School, Manila THE WORK CONCEPT Copyright © 2022 Saint Jude Catholic School, Manila WORK Work is a specific quantity resulting from a force that causes something to move a certain distance; or more technically, the scalar product of force and displacement. 𝑊 = 𝐹𝑑 Where: W - Work F - Net Force applied on a system d - displacement/distance traveled by the system caused by the force applied to it Copyright © 2022 Saint Jude Catholic School, Manila THE JOULE UNIT 1 Joule (J) of Work is equal to 1 Newton (N) of Force applied to an object causing it to be displaced at a length of 1 meter (m). 1 Joule = (1 Newton)(1 meter) Copyright © 2022 Saint Jude Catholic School, Manila THE PARALLEL CONDITION WORK can only be done if the force exerted to an object is parallel with the direction where the object is displaced. Work = Force||displacement What happens if the object travels at an angle? WORK is still done but only to a certain degree. The component of this displacement that id parallel to the force applied to it can still produce work. Work = Fdcos𝜽 Copyright © 2022 Saint Jude Catholic School, Manila WORK OR NO WORK? Copyright © 2022 Saint Jude Catholic School, Manila  PUSHING A TABLE WORK IS DONE Copyright © 2022 Saint Jude Catholic School, Manila  SITTING DOWN NO WORK IS DONE Copyright © 2022 Saint Jude Catholic School, Manila CARRYING GROCERY BAGS WHILE WALKING NO WORK IS DONE Copyright © 2022 Saint Jude Catholic School, Manila PRACTICE PROBLEMS Copyright © 2022 Saint Jude Catholic School, Manila  SUPPOSE YOU ARE PUSHING A CHAIR WITH A 500 NEWTON FOR CE ALONG A 7-METER AISLE. HOW MUCH WOR K IS DONE IN PUSHING THE CHAIR FROM ONE END OF THE AISLE TO THE OTHER? Copyright © 2022 Saint Jude Catholic School, Manila  SUPPOSE THAT YOU APPLY A 60-N HORIZONTAL FORCE TO A 32-KG PACKAGE, WHICH PUSHES IT 4 METERS ACROSS A MAILROOM FLOOR. HOW MUCH WORK DO YOU DO ON THE PACKAGE? Copyright © 2022 Saint Jude Catholic School, Manila  FIVE FOOTBALL PLAYER PUSH A 300.0 KG SLED ACROSS THE FIELD. THE SLED IS ACCELERATING AT 0.25 M/S PER SECOND WITH NEGLIGIBLE FRICTION. WHAT IS THE WORK DONE ON THE SLED BY THE FOOTBALL PLAYER OVER 15.0 M OF PUSHING? Copyright © 2022 Saint Jude Catholic School, Manila DETERMINE THE WORK YOU DO WHEN YOU EXERT A FORCE OF 3N AT AN ANGLE OF 45 DEGREES FROM THE DIRECTION OF MOTION FOR 1 M. Copyright © 2022 Saint Jude Catholic School, Manila A 5-KILOGRAM OBJECT TRAVELLED A TOTAL OF 12 METERS ON AN INCLINED PLANE AT ANGLE OF 30 DEGREES FROM THE FLOOR. IF THE OBJECT'S ACCELERATION IS 4 M/S/S, WHAT AMOUNT OF WORK IS DONE ON THE OBJECT? Copyright © 2022 Saint Jude Catholic School, Manila POSITIVE, NEGATIVE, AND ZERO WORK Copyright © 2022 Saint Jude Catholic School, Manila POSITIVE WORK WORK IS POSITIVE WHEN THE ANGLE BETWEEN FORCE AND DISPLACEMENT IS 𝜽 < 90 degrees. THIS MEANS THAT THE WORK IS DONE ON THE SYSTEM. Copyright © 2022 Saint Jude Catholic School, Manila NEGATIVE WORK WORK IS NEGATIVE WHEN THE ANGLE BETWEEN FORCE AND DISPLACEMENT IS 𝜽 > 90 degrees. THIS MEANS THAT THE WORK IS DONE BY THE SYSTEM. Copyright © 2022 Saint Jude Catholic School, Manila ZERO WORK WORK IS ZERO WHEN THE ANGLE BETWEEN FORCE AND DISPLACEMENT IS 𝜽 = 90 degrees. THIS MEANS THAT THERE IS NO WORK DONE BY OR ON THE SYSTEM. Copyright © 2022 Saint Jude Catholic School, Manila POSITIVE, NEGATIVE, AND ZERO WORK Copyright © 2022 Saint Jude Catholic School, Manila WHAT DOES A NEGATIVE WORK MEAN? Copyright © 2022 Saint Jude Catholic School, Manila Suppose there is an apple falling from a certain height. The force of gravity pulls it down. Since the Displacement displacement of the apple is parallel to the direction of the Gravitational Force gravitational force that it experiences, the earth is doing POSITIVE WORK on the apple. Copyright © 2022 Saint Jude Catholic School, Manila However, if we consider the non- Air Resistance conservative forces acting on the apple like the air resistance or the drag force that acts on it Displacement upwardly, these forces are anti-parallel with the displacement of the apple. Meaning, it does NEGATIVE WORK on the apple. Copyright © 2022 Saint Jude Catholic School, Manila  Air Resistance The upward forces slow the apple down by an infinitesimally small Displacement amount. This slowing down decreases the apple's KINETIC ENERGY. Copyright © 2022 Saint Jude Catholic School, Manila  Air Resistance THANK YOU FOR LISTENING! TOGETHER LET US ALL DO THE Displacement Fd Copyright © 2022 Saint Jude Catholic School, Manila